Suggestion 1: Futuristic.
Why? Because futuristic builds are a big part of simpleplanes now, and futuristic looking planes get tagged with "Experimental" even if the "Experimental" tag doesn't really fit such builds. Plus, when searching with tags, it would be very convenient for someone who wants to see some futuristic builds to just enter the "Futuristic" tag.
Suggestion 2: Mechs.
They are a growing build on SP. Plus, every other vehicle seems to have its own tag (Ships, Spacecraft, etc).
@Thehtmguy Hybrid is more usefull for hyv)brid engine plane (jet and propeller combination). Propably tags like amphibic (For land and water) or air vehicle (flying car) would fit.
or hybrid tag for things that fly, drive, and water drive/fly (can't think of the term)
we need a 'MURICA tag, cause 'MURICA
a roleplay tag for roleplay builds