Someone hired the beginning of this year is right around 2000, so at 50% and at current Airbus crewing approximately 16-16.2 crews, they would need a 60-70 plane order to get to the 250 airframes needed to support 4000 pilots. There’s a pretty margin margin of error as additional bases, a different aircraft type, and other factors (light attrition/retirements/senior FO bypassing) could reduce that.

The other factor is the rate of future delivery past 2019, even at 1 a month that’s several years out.