On Saturday, the union said Jet2 was pursuing the cuts despite a range of alternative options put forward by Balpa.
Several other airlines have announced job cuts after a collapse in demand caused by the pandemic, including British Airways, easyJet and Ryanair.
Balpa General Secretary Brian Strutton said: “This announcement is another which shows the desperate state of the UK aviation industry.
“Despite huge efforts to work with Jet2 to find ways to save these jobs, the airline is insisting on 102 layoffs.
“It will be a particular kick in the teeth, as many of those at risk of losing their jobs recently joined the airline after being fired from Thomas Cook, who took office last year.
Mr Strutton called for support from the industry which has also been affected by the establishment of quarantines for travelers to various vacation destinations.
He said: “The government has an important role to play in supporting the vital UK aviation industry. His quarantine changes continue to throw every reboot plan into chaos.
“If these quarantines are really necessary, the government must mobilize its support to help the airline industry which is doing its best to get back on track but continues to be pushed back every moment.”
Jet2 has been contacted for comment.