CAT 1234 has provided the best explaination. Upper Sideband and Lower sideband operations are identical for operational purposes however. The reason that aviation uses USB is simply convention. Just as aviation uses the technically inferior AM for VHF comms, it's just a convention that cannot be changed.
The only services that use LSB are amateur and citizen radio services, so don't worry about them.
I think that this is a good question, and please dont be intimidated away from asking good questions here.
I don't know of any aviation radios that offer LSB as a user option, and knowing more than basic radio operation from a user perspective is unnecessary for pilots.
Even most avionics LAME's wouldn't know the answer to your question, and to this end CAT 1234 has surprised me.