After bowing to the awesome power of an Icelandic volcano in April, international air travel rebounded nicely in May and is now flying above even pre-recession levels.

The International Air Transport Association (IATA) says passenger traffic was up 11.7% compared to May of 2009, while freight demand spiked 34.3%. "Passenger traffic is now 1% above pre-recession levels," according to IATA's Giovanni Bisignani, "while the freight market is 6% bigger."

Which U.S. airlines had the merriest month of May? Continental and American Airlines were probably happiest to see the volcano behave. Each gathered over 40% of its revenue from non-domestic flights last year:

Airline

Domestic Revenue

Non-Domestic Revenue

Total

% Non-Domestic

Continental Airlines (NYSE: CAL)

$6,941

$5,645

$12,586

45%

AMR Corp. (NYSE: AMR)

$11,974

$7,943

$19,917

40%

UAL Corp. (Nasdaq: UAUA)

$10,775

$5,560

$16,335

34%

Delta Air Lines (NYSE: DAL)

$19,171

$8,892

$28,063

32%

US Airways (NYSE: LCC)

$8,285

$2,173

$10,458

21%

Data from Capital IQ. Revenue numbers in millions.

Fool analyst Rex Moore knows the joy of the ocean like a boy knows the joy of his milkshake in motion. He owns no companies mentioned in this article. The Motley Fool has a disclosure policy.