But turbulence has continued for BER during its first year of operation, with a long list of problems and passenger complaints: lengthy check-in and security lines; confusing layout and signage; cramped, dirty bathrooms; and bacteria found in drinking water, just to name a few.

Most recently, a fire alarm on November 5, which was possibly triggered by a passenger smoking in a restroom, resulted in an evacuation and, for many passengers, another security check mandated by the federal police, even if they had already been screened. Although many departures were held back to accommodate the delay, travelers still missed their flights.

That was preceded by another challenging situation in early October during Germany's fall school holidays, a popular travel time for locals. Hours-long check-in and security lines again led to missed flights and irate passengers, some venting their frustrations on social media with videos and photos of lines snaking through the airport. Others reported long waits for baggage pickup.

The airport, which is owned by the federal government and states of Berlin and Brandenburg, also faces a financial crisis. With passenger numbers a fraction of pre-pandemic figures, the company lost approximately $1.16 billion in 2020, with more high losses expected in coming years. By 2026, BER will require an additional 2.4 billion euros. "We need money quickly," CEO Aletta von Massenbach recently told German newspaper Tagesspiegel.

Perhaps not surprisingly, a parody Twitter account popped up in November "supporting Berlin Airport in apologizing to travelers."

Staffing shortages and pandemic challenges

During an interview at BER, airport spokesperson Jan-Peter Haack acknowledged the problems and emphasized that management and staff are diligently working on improving the passenger experience. "We had some days [where] we faced issues, and we didn't provide the service that travelers should get," Haack told CNN.

Haack pointed to several underlying factors behind long wait times, most notably staff shortages caused by the pandemic and a time-consuming, complex check-in process due to vaccine documentation and entry restrictions. As with other sectors of a decimated travel industry, many airport employees left for other jobs during the pandemic. Hiring new employees is even more difficult under strict government regulations regarding furloughs, Haack explained.

Matching labor needs to dynamic passenger volumes also has been a challenge. During the busy fall holiday period, BER anticipated it would see more than 900,000 passengers between October 8 and October 24. That Friday, October 8, the airport experienced its highest one-day passenger total, with some 67,000 travelers. However, the longest lines and other issues happened the following day, when there were fewer passengers (about 55,000) but also fewer staff because of shortages like employees calling in sick, Haack said.

The airport was filled with holiday travelers on July 1, 2021.

"So we could see that it was a problem of the process and staff [shortages], not the infrastructure," Haack said. "It is a problem at the airport for all of our partners together. And we have to work with it together to improve. Of course we do work on that. And this issue is happening at airports around the world and airports all over Germany."

In addition, Swissport, one of the companies that provides ground services at BER, made several adjustments to operations following that weekend. The company dispatched a management team to the airport, ramped up its ground handling staff by 50 for a total of about 540 employees and adjusted shift schedules "to reduce the strain on our operation," Swissport told CNN via email. "Swissport is in a regular dialogue and close exchange with its customers and partners at Berlin Airport. The aim is to jointly improve the services for airlines and passengers."

However, some passengers have already lost patience with BER. Kunal Saigal, a professor at a private university in Berlin, described the airport as "absolute chaos" in early September when he, his wife, and their one-year-old son arrived the recommended three hours before their Lufthansa flight to New Delhi to visit family.

Navigating the lengthy check-in and security lines took hours, and airline and security staff were unfriendly and unhelpful, Saigal said. The family ended up missing their flight, which Lufthansa staff rebooked at no charge for the following day. Still, Saigal estimates he lost about $340 for required Covid tests and taxis to and from the airport, which he's received no reimbursement for.

The experience has left him hesitant to fly out of BER again -- and nostalgic for its now-closed predecessor, Berlin Tegel, the outdated but beloved Cold War relic.

"You could pull up your car at the curb and walk to your gate in two minutes and be at the boarding gate in 10 minutes," Saigal said. "It was so much more efficient, and Germans are very big on this efficiency aspect. That was truly efficient. This is the exact opposite."

Ian Clark, a Berlin-based bank accountant who has lived in Europe since 2018, so far hasn't missed any of his three departures out of BER. Nevertheless, the lengthy queues and overall frustration he has experienced have him rethinking options for future travel, in addition to what he'll advise family members who visit him in the future.

"I will do everything that I can in the future to avoid Berlin airport because I just don't want to deal with the stress," Clark said. "If I do miss my flight or I don't miss my flight, I'm going to be stressed out about it either way because of just how terrible it is."

'We definitely have empathy'

Haack said airport staff take such complaints seriously. "I would say to those people, number one, that we definitely have empathy," he told CNN. "And maybe you will try to give it [another] shot. We are improving hopefully every day."

Initiatives on that front include a task force, known as the BER Team, which was implemented during the fall holiday period and spans about 40 employees per day across security, check-in and baggage handling to help fill the gaps and assist passengers, Haack said. The program will start again in mid-December to try to ensure a smooth experience for holiday travelers.

In addition, Haack said BER is also focused on improving the security screening process -- another common passenger complaint. Until recently, there was very limited space for passengers to unload laptops and liquids before entering the scanning equipment, leading to bottlenecks and slow-moving lines.

Haack said extra tables have now been added to some security lines to provide more room and speed up the process.

Whether such measures played a role or not, there were almost no lines on a recent Friday afternoon at BER's security or check-in areas, even for budget carriers where long queues are common. Security required less than 10 minutes to get through, even with a pat-down. Staff, from an agent at the information desk to security agents to restaurant personnel, were friendly and helpful.

However, some bathrooms were dirty, with broken bag hooks in stalls and water puddling across sink counters. Several moving walkways weren't in operation. And, in perhaps the most glaring reminder that BER's infrastructure dates to another era, portable charging stations, instead of the in-seat power outlets standard at many modern airports, stood at some boarding areas.

Haack said the lack of outlets is another common passenger complaint. He explained that airport officials were aware of the issue during the construction process but decided to proceed regardless in order to avoid further delays in opening BER. A fix is in the budget, he said, but taking precedence are more pressing issues, such as preparing for holiday travelers.

'Not a nightmare for everyone'

Indeed, BER faces its next big test with the upcoming holiday travel season. Since December 1, the airport has been operating two parallel runways (before that, it was alternating them, except for a brief period following its opening). It's hoped this development will improve flexibility and "stabilize air traffic" in case of winter weather disruptions, such as one runway requiring de-icing, Haack said.

In addition, based on passenger feedback, management has also installed more seating in waiting areas, adjusted cleaning schedules and improved navigation, Haack added.

By end of March 2022, before the busy Easter holiday week, the airport aims to open Terminal 2, which has remained closed because of low passenger numbers. "We'll maybe have a soft launch before, with maybe one flight a day, two flights, so you can be sure when you really need the extra facilities it works smoothly," Haack said.

BER estimates it will have seen 10 million travelers in 2021 -- less than a third of its predecessors, Tegel and Schönefeld, combined in 2019. But not all passengers are disgruntled. Jenn M. Choi, a Berlin-based empowerment coach and writer who has traveled twice from BER with her husband and baby son, says she was "shocked" by how smooth both her experiences were after reading so many complaints on social media and elsewhere.

Choi says her family had no issues with the check-in or security processes, even with a stroller as bulky baggage. Furthermore, an airport staffer sought them out to point out the security line dedicated to families and passengers with disabilities. "That just made the experience feel, to be honest, pretty VIP," Choi told CNN.

Choi was also impressed by the dedicated, spacious family bathrooms. And while she understands the frustrations of many other travelers, she also points out that "the airport isn't a nightmare for everyone."