Those with American or United flights should check their ticket for changes, even if the original flights were not on Max 8 or 9 aircraft, since the airlines could be swapping other aircraft around to cover the flights originally using those aircraft.
If you have a pre-assigned seat or upgrade seat, check on that as well, since different aircraft (even the same model with different interior) have different seat arrangements that can invalidate original pre-assigned seats.
Phoenix Sky Harbor airport seems to be a parking lot for some Max 8 aircraft, since both Southwest and American have maintenance bases there. Southwest is moving other Max 8 aircraft in its fleet to where it has other maintenance bases. Southwest cancelled 39 out of 4,000 flights on Thursday.
Flights out of Miami were significantly impacted, because American based 24 Max 8 aircraft there. Other American flights have been impacted due to reallocating other aircraft. Some Max 8 aircraft have been moved to one of American’s maintenance bases in Tulsa.
https://www.miamiherald.com/news/business/tourism-cruises/article227792119.html
Sully’s take on the crash.
Who is flying these planes to wherever they’re to be parked? Volunteers?
A true hero, thank you for sharing that.
Presumably pilots who are employees of the airlines whose planes they are.
From comments.
MCAS- Might Crash Any Second
@ucbalumnus But did they have any say in that assignment?
@BunsenBurner I wish they would change that moniker.
MCAS is the liberal arts and science college at BC. Morrissey College of Arts and Sciences !
#-o
Perhaps an airline pilot would be more qualified to explain how airline pilots are assigned to flights.
I thought it was Marine Corps Air Station.
In the context of the Max 8, MCAS means “Maneuvering Characteristics Augmentation System”.
This “MCAS” discussion is exactly why I hate the overuse of acronyms. Too ambiguous.
I had heard that the FAA grounding order allowed the Max’s to be ferried with no passengers onboard. As far as who is flying them, I would guess the same pilots who were flying them before. Trips put into open time for trade, trips revised, pilots on reserve assigned. If someone objected, they probably would not be forced to take the trip. However, I guarantee you, people will do anything for $$. And they are all got the 20 minute slide show that barely helps, so there’s that. 
I’m reading things on private forums about this airplane that I don’t want to repost, and I’m horrified. We are really fortunate that this kind of accident hasn’t happened in the US. We can be so confident about our highly trained pilots and top notch maintenance, but much of this is due to luck.
At least two Max planes are on Maui airport, I believe, taking up a lot of space. Hopefully they will be ferried and parked elsewhere.
I was under the impression that these grounded planes were allowed one…one way trip to wherever they need to go while grounded. What a logistics mess. Guessing the airlines using these planes needed to do some planning.
How many were in use by U.S. airlines?
https://www.faa.gov/news/updates/media/Emergency_Order.pdf page 2 covers the topic of flying the planes without passengers to move them for storage, repairs, testing, etc…
34 Southwest
24 American
14 United (Max 9)
I don’t know. If it takes a couple of legs to get to the base they are trying to relocate them to, maybe they’ll allow them more than one. Regardless, there won’t be any pax onboard.
@busdriver11 , thanks for the update and letting us know these are not good planes, skilled pilots or not. I also got that impression by reading Sully’s statement. I wonder even if they get “fixed”, if people will be looking now st the plane that’s flying when they book their trips, and go on another airline or flight if they see it.
I’m not flying them.