DUBAI (Reuters) -Global airlines on Monday raised their profit forecast for 2024 and projected industry wide revenues just shy of $1 trillion as a record number of travellers board flights.

The International Air Transport Association (IATA) said it expected the worldwide industry to generate $30.5 billion of profit this year, higher than an upwardly revised $27.4 billion in 2023 as carriers keep a lid on underlying labour costs despite recent strikes.

That comes just four years after the industry collapsed to a $140 billion loss in 2020 as a result of the pandemic and is above the $25.7 billion forecast for 2024 issued in December.

"The environment is better than we had expected, particularly in Asia," Director General Willie Walsh told Reuters on the sidelines of an annual meeting of IATA's more than 300 members, which account for more than 80% of global air traffic.

However, the airline industry warned its ability to serve a strong rebound in travel demand is being hampered by disruption to global supply chains, including deliveries of its own fleets.

Passenger yields - or the average amount paid by a passenger to fly one mile - are expected to strengthen by 3.2% compared with 2023, IATA said in a twice-yearly economic outlook. In part, that is because capacity growth is constrained, driving up average fares.

By contrast, the corresponding figure for cargo is expected to fall 17.5% in 2024 as freight markets return towards normal patterns after booming during the pandemic.

Airline activity is widely seen as a litmus test for business or consumer confidence, as well as trade.

The industry has high fixed costs and regulations that discourage most cross-border mergers, meaning it remains fragmented.

"The margin remains wafer thin; we're still looking at a margin of just over 3%," Walsh said. "(That) performance is still well below where the industry needs to be."

In Asia, IATA more than trebled its industry profit forecast for 2024 to $2.2 billion despite a sluggish recovery in international travel in China.

At $14.9 billion, unchanged from earlier forecasts, North America remains the most profitable region with "strong consumer spending despite cost-of-living pressure," IATA said.

IATA said airlines had been hit by unforeseen maintenance issues. That appeared to be a reference to repair bottlenecks for engines built by Pratt & Whitney, which are expected to leave hundreds of Airbus jets grounded this summer.

Industry sources said on Friday that Airbus, the world's largest planemaker, was itself facing a new surge in supply problems, casting doubt on output plans for the second half. The planemaker has said it is sticking by full-year delivery goals.

Rival Boeing ( BA ) is producing far fewer of its best-selling 737 MAX jets than originally planned after a mid-air cabin panel blowout in January prompted U.S. regulators to cap its production.

IATA's 2025 annual general meeting will be held in Delhi, India, hosted by Indian carrier IndiGo, the organisation said on Monday.

(Additional reporting by Aditi Shah and Alexander Cornwell; Editing by Jamie Freed)