A bit of back of the beer coaster calculations, with the current rate of burning through cash through to late 2021, the extreme cost of RINing, retraining and redundancies through the pilot group would burn the cash so quick that date would be reached far sooner. And that’s just in the pilot group.
More likely than that:
Indefinite stand-downs until future retraining is available (as long as there is a plan to fly in the future no matter what the date a stand down can be effected until that point)
Arrangements are made for alternative work positions for stood down crew until pilot positions are available (positions more substantial than Woolies or Coles but not flying aircraft).
Some incentives for crew who take early retirement
But mostly I think stand downs on a rotating basis to allow excess crew numbers to be absorbed until things return to normal. Basically job sharing, but of course will mean a loss of overall income.
I guess the crew as a whole will have to decide whether they would prefer a system of rotating stand-downs for several years and the associated loss of total income but more people will keep their jobs....
.... or a RIN’s retraining and redundancies that’ll be expensive and probably see a fair few of of the most junior and youngest crew made redundant and be on the streets without work....