Unite assistant general secretary Diana Holland said an end to the furlough scheme this month would result in more jobs being "needlessly lost".
Holland said aviation was in particular need of supports, with its recovery "still delayed". "Unlike any other sector, [it] is hugely reliant on the lifting of international restrictions," said Holland.
"As a minimum, the furlough scheme should continue for the aviation sector. A failure to do so will dramatically damage the long-term recovery of this critical sector to the UK economy."