Balpa said the coronavirus crisis had created a surplus of pilots who were now in competition for fewer jobs, with many airlines trimming their schedules owing to the pandemic.
Youngsters keen to take to the skies are instead advised to gain experience in another profession before looking to enter the industry once it has started to recover from the Covid crisis.
The union has warned students otherwise risk paying upwards of £100,000 for their training only to find there are no jobs available once they qualify.
Wendy Pursey, Balpa’s head of membership and careers services, said: “There are currently 10,000 unemployed commercial pilots across Europe, including 1,600 pilots in the UK.
“Many pilots are working part time or on reduced pay to save jobs. And there are already around 200 trainees in flight training schools who were on a path to jobs with easyJet who now have no clear route to even a licence, far less a job.
“This is not a positive picture for anyone whose heart is set on entering this profession. There will be fewer jobs, with more people competing for each one even once this pandemic is over.
“In this situation, it would be irresponsible if we did anything other than warn people to consider delaying their flight training at this time.”
Pursey added: “We urge potential pilots to get experience in another profession first which will postpone any training until the industry is in a more robust shape, provide additional skills and experience and also give them another avenue to fall back on.
“For anyone that still wants to proceed they should consider the Modular training route which does provide the opportunity to learn and work in other fields.”