Again there are two separate issues here, and while not entirely unrelated, have to be looked at separately for context. The first is how many pilots we need to fly X number of aircraft, and the second is how productive each aircraft is.

If the airline wanted, we could run the ratio of reserve to line pilots up to 50/50 and never see another red day again. Obviously this would not be the most efficient use of crews, and productivity of each plane would go down.

Ideally you want each plane flying as much as possible, but to do this you need an appropriate amount of reserve pilots to absorb any disruption, be it internal (sick, vacation, training) or external (weather, airspace, disaster).

Forget future deliveries for a moment, we have enough pilots to fly all current aircraft. However recent history has shown an inability to absorb network disruptions effectively. This is a result of several factors ranging from frequency to mismanagement of communication and coordination. Lack of, or inexperienced schedulers, unacceptable hold times, useable crews timing out, etc.

If we stopped growth at the current 160ish aircraft, these issues would still continue if those factors aren’t fixed. Adjusting the ratio of reserves and reducing routes is a short term solution, but doesn’t remedy the underlying problem and doesn’t make the most efficient and profitable use of planes and crew.

As for growth, if recruitment and attrition problems were the main reason for the operational issues, the company would almost immediately want to open section 6 talks.

Historically carriers like NK, F9, and even B6 were alternative career paths. Low pay regionals would compel pilots to consider these alternatives, and lifestyle and advancement is what made so many stay. Now with several regionals who have actual route cancelling shortages upping pay, staying and flowing becomes more palatable. Look at the change the last 10 years at the regionals: signing/retention bonuses, guaranteed basing, hotels for commuters, pre hiring of low hour candidates, etc. It’s only when this has a pressure on recruitment will the alternative majors decide to throw money at it.

For now, they won’t park planes or delay orders, they will just fly planes with less optimal efficiency.

TL/DR: at the moment we are not short staffed, the problems are operational, but as the choice to wait it out in the regionals for the legacy call becomes more preferable and our total pilot count recedes, the problem will compound unless pay/lifestyle is addressed.