After flying with the RFC 11 for a while, the Bristol Scout was withdrawn around July and replaced with the FE2b. Problem is that there were no observers, so no missions would generate and time would automatically advance by one day. So, I advanced time until December with no observers and no missions and in that month, the whole squad were assigned FE2bs.
Oh well, I will probably need to revert to a previous save and transfer out of that squad.