To improve a bit the organization how about:
1 - Double the points / perks if you are flying into a mission.
2 - Make a "mission wizzard". An easy version of the mission editor where you simply put initial field number, target field number.
3 - Add an option to assign general plane type in the slots. That is, flight #1, any fighter. flight #2, any bomber, etc. Same for loadouts (free loadout).
4 - Dont let the people to mess with the "take off runaway", once the mission is up, the first player (editor?) going out in the mission decides the take off runaway and the rest of planes use the same one.
A Wizzard example:
1 - Mission: CAP from A23 to A23
2 - Flight #1: Any fighter, any loadout, unlimited slots.
3 - Starts in 5 mins, 10 mins more to join
GO.
Now there is the problem of advertising people about submitted missions. You may use the clipboard window adding at the bottom a dropdown list with the current submitted missions and starting times. And an icon (exclamation) at the left of the list that is activated for 2 mins each time a new mission is submitted, add also a .wav sound notifying the post of a mission. This way the people will be able to get some information about mission while in flight with only the clipboard window open and not obscuring their entire screen with the map window.
Also, it would be very good to have the chance to edit new missions while inflight. These 5 - 10 mins doing nothing but climbing would be well invested into editting missions.