A set piece Staged Mission can have a very sterile feel when only the principal aircraft are involved. It is very obvious that you are in a completely empty world expect for the few planes directly involved in the mission.
It is nice to flesh out the mission universe with a cast of background "extras" that going about their business separate from the primary mission, like recon, patrol, field ops, etc. That gives more of a living world feel.
However these other flights are not intended to be player selected. Players would find their roles very boring. Like take off from a field, circle twice, land. Etc.
You can get around this sorta by naming those flights "Do not Select" to clue the user in the flight selection combobox to not choose them, but that is awkward, and spams up the list with a bunch of junk. It is rude to present the user with lots of items you don't want the to select, but they will have to scroll through to get to what they want.
It's not a huge deal, but it would be nice to have a checkbox on the flight properties definition dialog in the Mission Editor that is off by default: "Suppress Flight Listing". You could check it and those flights are excluded from the selections offered to a user when configuring a mission. If you ever happen to be in that area making other changes, this would be a nice feature.

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CptTrips