Airlines are in a festive mood, reflecting a forecast for heavy holiday travel, a record year for global industry profits and improving unit revenue in the U.S.

Industry trade group Airlines for America said Thursday that 45.2 million passengers will fly globally on U.S. airlines during the 21-day period that begins Friday, Dec. 16. The number is up 3.5% from 2015.

If current trends continue, U.S. airlines will carry a record number of passengers this year, exceeding the total of 798 million passengers in 2015.

"An improving economy and reduced airfares remain the driving force behind the growth seen in air travel," said John Heimlich, A4A chief economist, in a prepared statement.

For the global airline industry, the International Air Transport Association, which represents 265 global airlines, projects a record net profit of $35.6 billion, with more than half of that provided by U.S. carriers. Looking ahead, IATA expects a decline to global profits of $29.8 billion in 2017.

"Airlines continue to deliver strong results," said Alexandre de Juniac, IATA's director general and CEO, in a prepared statement. "Even though conditions in 2017 will be more difficult with rising oil prices, we see the industry earning $29.8 billion. That's a very soft landing and safely in profitable territory. These three years are the best performance in the industry's history - irrespective of the many uncertainties we face.

"Indeed, risks are abundant: political, economic and security among them," de Juniac said. "And controlling costs is still a constant battle in our hyper-competitive industry,"

As for the U.S industry, "We should also recognize that profits are not evenly spread with the strongest performance concentrated in North America," de Juniac said.

For U.S. carriers, IATA expects post-tax profits of $20.3 billion in 2016, with a decline to $18.1 billion in 2017. Net margin is expected to be 8.5%, the best in the world. "Recent consolidation continues to underpin the region's strong profitability, even as the region faces upwards cost pressures which include the price of fuel," IATA said.

Last week, Delta Air Lines (DAL) - Get Report reported that consolidated passenger revenue per available seat mile declined 1% in November, ahead of analysts' expectations that called for a decline of 2% to 3%. October was the 19th consecutive month of domestic PRASM declines and the 29th consecutive month of international declines.

Investors have focused on the declines, even though they result largely from the positive impact of declining oil prices, which also drag down fares, revenues and PRASM.

But industry shares got a boost in November, when famous Warren Buffett's Berkshire Hathaway disclosed in a filing that during the third quarter it had acquired airline shares valued on Sept. 30 at about $1.3 billion. American (AAL) - Get Report shares accounted for the lion's share, about $800 million.

American CEO Doug Parker said Wednesday that the U.S. airline industry has been transformed, largely due to consolidation, and now represents a viable long-term investment vehicle for the first time. "The Berkshire Hathaway investment is as good as any validation for that," Parker told CNBC's "Squawk Box."

While noting the many comments Buffet has made regarding the sector in the past, one in particular stands out in Parker's mind. "My favorite quote he has is 'you get the shareholders you deserve' and the reality is we didn't deserve shareholders like that in the business we had before," Parker said.

Year to date, United shares are up 25%, American shares are up 13% and Delta shares are flat.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.