Yes you can. No you shoudn't. If anything happens, you'll have to eat a missed trip and one that will be extremely expensive and disruptive for the company and it won't go over well.

Nope. wudnt think so. But we have a track record of being pretty astute bargain shoppers when it comes to aircraft.
While a single type fleet has advantages...if there is a grounding it shuts the whole operation down. So a fleet mix of aircraft is a way to offset.
If boeing offered Delta a smoking deal on some cancelled Max orders....does anyone think we wudnt seriously look at them?

I get all that. But we'd have a mixed fleet regardless of that. I'm just wondering if we did get some MAX aircraft would they be growth (or in leiu of some other future order) or would we have to take it out of existing AB orders?

Wouldnt think at the expense of any current plans.

We have well over 200 NB airframes nearing retirement. (752-3 md80-90) not including 80+ 737-8s that are past middle age...and another bunch of 717s...without accounting for growth.

Delta is gona need all aircraft on order plus a bunch.

Plus some of the original 320s are getting up there in age.

Yup. True dat. Add another 100+ to the total for the 319-20s..
The GTF adds huge operati g economies. So 220 and 321 neo are gona predominate. But next best is the GE Leap on the Max.
The fleet mix strategy for avoiding a complete shutdown of an airline is not just an airframe consideration. Its engines too.

Any speculation on when (if ever) LAX is going to become a 220 base?

If the 220 ends up being as successful as it seems to have the potential for, I expect you'll eventually see it in every base. I wouldn't be surprised if a new base for it was announced in the next 18 months.

BS already has eluded that we may see a new A220 base in the next AE.

I think DTW220 would be the most likely candidate for the next base.

It's going to be flying out of DTW by then (if it hasn't already started) and in addition to that, it seems like the initial signs of 717 drawdown from non-ATL bases have appeared. Something will fill that void but that's more of 2-5 year plan I'd imagine.

But, if the 717s might be gone in five years, then they'll certainly be relegated to ATL-only just as the 88s are, perhaps only 3-5 years from now.