As already answered by the other members, yes this prevents you from getting the rewards and there is a trick to get them nevertheless by editing the missions files.
What I do is always do the mission once with the default plane, just to see what happens, and to determine what kind of plane can really be used or not.
For example, After flying the Denali Camp mission, I understood it would be cool to do it with an helicopter (I did it with the Merlin and the Super Puma from Dirk Fassbender), and set the flight time to one hour before the sun goes down. That was a total blast.
I also did a similar thing with that easy mission, the one with the Baron where you have to fly from a field to another, starting from Stehekin Lake, and in the end one of your engines dies shortly after takeoff. I changed the flight time to the evening as well, and choosed the DC-3. That was challenging for some airports, but overall it was really cool.