Global airline share prices are up 20% year on year following a further 7.8% rise last month, according to international airline body IATA.
European carriers saw the biggest rise of 14%, although gains were seen in all three global regions.
IATA said prices were up despite a squeeze on airline profit margins due to higher costs and weak yields in May.
Passenger growth continued and load factors reached a record high during the month, although yields remained 3% to 5% lower than a year ago.
Jet fuel prices continued to fall in May, when they were down by 5.6% for the month overall.
