Yes, you certainly have the option of waiting for the ME which I regularly use to edit missions. However, you can also do it manually as well.

If you install the airfields MOD which contain the training airfields, then you're more than halfway done. After that, you get the latitude and longitude of each airfield from the global_layer.csv file and save it somewhere. Then when the pop-up appears to edit the mission, just enter the long/lat as takeoff and landing of your flight, Remove all waypoints between takeoff and landing, so you're just left with those two rows. Then remove ALL flights/waypoints from the mission file and just leave your sqd row. Then save and close.

And you're all set. you'll start at the training field and use the inflight map (and/or terrain) as a guide to your flight path. Then After you're done with a training, you can use the wonderful pilot log editor to edit your mission description or you can do that manually as well.