It was a record year for bankruptcies, as travel giant Thomas Cook went bust, and close to 20 other airlines besides.

There were bad times for Boeing, with its 737 MAX grounded since March after being involved in two fatal air crashes.

New mega-airports opened around the world, with Singapore's Jewel Changi Airport -- complete with indoor waterfall -- the most spectacular of all.

More flights were taken than ever before, and the industry faced a shortage of both pilots and airport slots -- but at the same time a global "flight shame" movement, spearheaded by a teenage climate activist named Greta Thunberg, gathered steam.

Here's a look back at the year's most talked-about moments in aviation.

The new era of ultra-long haul

In November, an experimental research flight operated by Australian airline Qantas flew nonstop from London to Sydney, smashing two aviation records.

Flight QF7879 became the world's longest passenger flight by a commercial airline both for distance, at 17,800 kilometers (about 11,060 miles), and for duration in the air, at 19 hours and 19 minutes.

The achievement could help usher in a new generation of ultra-long-haul flights that will directly connect Sydney with destinations across Europe and the United States.

The 'world's best airport' got even better

Following four years of construction, Singapore's long-awaited Jewel Changi Airport officially opened in April.

Featuring a dramatic, doughnut-shaped exterior framed in steel and glass, the 135,700-square-meter (around 1.46 million square feet) space is a multi-use complex designed to connect three of Changi Airport's four terminals.

The star attraction is the 40-meter-tall (around 130 feet) HSBC Rain Vortex, which cascades through a huge oculus in the middle of Jewel and is billed as the world's tallest indoor waterfall.

The airport -- regularly voted the "world's best" -- is so popular that in September the Singapore Police Force issued a warning to residents not to "misuse" their boarding passes after a man was arrested for buying a ticket just to walk his wife to the gate.

Anyone caught accessing the gate-side areas at Changi without intending to fly faces fines of up to S$20,000 (US$14,300) or a two-year prison term.

New airports, from Beijing to Berlin

China's new mega-airport, the $11.5 billion Beijing Daxing International Airport, designed by the late architect Zaha Hadid and her Chinese partners with a striking starfish design, opened in September.

Construction started in May on a new international airport at the mouth of Peru's Sacred Valley, home to the mountaintop citadel of Machu Picchu. The project has sparked opposition from those concerned about the impact on the surrounding landscape.

A new $3.9 billion Delta terminal was unveiled at New York's unloved LaGuardia Airport, once compared by US presidential hopeful Joe Biden to a "third-world country."

And finally, after a nine-year delay, more than 8 billion euros and thousands of complaints over the budget and construction, Berlin Brandenburg Airport Willy Brandt eventually announced an opening date: October 2020.

Cabin innovations

Airbus, along with its design partner Safran, picked up a Crystal Cabin Award for its plans to create sleeper berths on its jets -- for passengers who don't mind sleeping in the cargo hold. The passenger modules will be available to airlines by 2021.

Aviointeriors premiered the third iteration of the notorious Skyrider 2.0, a stand-up airplane seat on which passengers perch as if on a bicycle. When we reported on it on April, the makers were still waiting on their first order from an airline.

Delta Air Lines reduced the recline of its airplane seats by two inches, in an effort to improve customer satisfaction and reduce in-air squabbles.

Colorado-based startup Molon Labe Seating unveiled its solution to the issue of the unpopular middle seat: three economy seats in a staggered layout, putting the middle seat slightly behind the aisle and window seats, and at a slightly lower height.

Molon Labe Seating's Hank Scott told CNN in July that the seats should be available on two airlines -- one North American -- by Spring 2020.

Misfires and mischief

There were some audacious criminals at New Delhi's Indira Gandhi International Airport, such as the 32-year-old man caught posing as a senior citizen and trying to board a flight to the US.

His disguise included a snowy white beard and turban and a passport claiming he was 81 years old.

However, he had nothing on 48-year-old Rajan Mahbubani, who donned the uniform of a Lufthansa pilot in order to fool airport workers into letting him bypass security lines and get seat upgrades. It apparently worked too, until he was caught in the act in November 2019.

Cathay Pacific's year got off to a bad start when it accidentally listed some first-class and business tickets at a discount of up to 95% -- then repeated the blunder two weeks later.

Virgin Atlantic was hauled over the coals for its very creepy in-flight seat messaging system, Pakistan Airlines got flak for a memo telling its cabin crew to lose weight, and not everyone was impressed when Japan Airlines introduced a baby seat map to allow passengers to sit further from the little ones.

Boeing and Airbus

In January, Boeing unveiled its Transonic Truss-Braced Wing concept, an extremely thin, folding wing with an extended span of 170 feet that, it says, will offer unprecedented aerodynamic efficiency.

The Boeing 777X made its muted debut in March, overshadowed by the grounding of the Boeing 737 MAX after the craft was involved in two fatal crashes. By year-end, there was no end in sight for the crisis, with the company suspending production of the jets in December.

In February, aviation fans around the world were dismayed at the news that Airbus was ceasing production of the A380, the world's largest ever passenger airplane. It plans to deliver the last of the superjumbo craft in 2021.

In June, Airbus unveiled designs for the A321XLR -- an aircraft it claims will be the world's "longest range single-aisle airliner." It's set to be rolled out in 2023.

Airbus also revealed a plane with flapping wings inspired by the albatross. The Albatross One, a model based on the A321, is constructed from carbon-fiber and glass-fiber-reinforced polymers and has "semi-aeroelastic" hinged wing-tips. It's currently in the testing stage.

Making the world a better place

In January, Etihad Airways flew the world's worst first commercial flight using locally produced biofuel.

In June, US airline passengers who don't identify as "male" or "female" were given more gender options to choose from when booking tickets, thanks to a move by Airlines for America (A4A), the industry trade group.

In August, San Francisco International Airport banned the sale of plastic water bottles as part of an effort to become the world's first zero-waste airport by 2021.

In an eco-conscious move in September, KLM announced plans to to partner with European train companies Thalys and NS to replace one of its five daily flights between Amsterdam and Brussels with a high-speed rail service.

In another measure to make life better, in October London's Gatwick Airport tested new boarding systems which it hopes could cut the airport's boarding times by 10%.

Wednesday, July 24, 2019 was one of the busiest days in aviation history, with more than 225,000 flights recorded by flight-tracking service FlightRadar24.

Global air traffic has been rising steadily over the past two decades, and with climate activism high on the news agenda this year, with Extinction Rebellion and Greta Thunberg regularly in the headlines, people around the world are starting to reconsider their high-carbon lifestyles.

"Greening" our vacations -- making travel more sustainable without relinquishing it entirely -- is one of the fastest growing movements in tourism. You can read more about this in CNN's green travel tips.