What you should know if you’re about to fly on a Boeing Max 9

Boeing 737 Max 9 jetliners are carrying passengers in the United States again for the first time since they were grounded after a panel blew out of the side of one of the planes.

Alaska Airlines resumed a limited number of flights with its Max 9s on Friday. United aims to follow suit on Sunday, but a spokeswoman said the airline might use them as spare planes Friday or Saturday.