Since the use of mission screens in-flight is not desired, I took another approach with this one. I have a new version under development that will be quite different. For in-flight distances, use updating tsc. For in-flight markets, I managed to create a cool hack that I have not seen around before. You need an asc equipment and then you need to cycle to a station with a beacon. Station buoy will also do. Now open up f8 market screen and be surprised
It works so that when you're in-flight and open up the market screen, it checks you compass target and if it's a station, it temporarily changes the system name to the station name and market to the compass target market. System name and market data are restored immediately after the market screen is shown.
If there's some obvious problem here or something breaks badly, please let me know. I seriously tried to think of possible problems, but did not find any actual ones. In practice the main station market gets overwritten by the oxp station market while the player switches to the market screen, so if there's an oxp out there that tries to alter the main station market exactly that same moment, then that change will reset. System name also gets overwritten by the station name, but that will be very brief too, from guiScreenWillChange to guiScreenChanged. The only case I could think of was an oxp waiting for a market change using a framecallback. I'm not aware of such an oxp.
The in-game rationalization is of course that the beacon it self contains the market data, as well as station name.
Download here: market inquirer 1.7 wip1