They used gliders due to the fact that engines are hard to make/power. Also aluminum(useful due to weight to strength ratio) was very rare. Gliders also laid the framework to useful powered aircraft designs.
Because people hadn't figured out how to make and fly powered aircraft in 1900. No one made a successful flight in a powered aircraft till 1903.
On their powered aircraft yes, they first experimented with gliders that didn't have an engine.
The first powered aircraft with a name seems to be the "Wright Flyer I" ... although they built and flew many gliders before that.
They made at least 2 gliders before their first powered aircraft.
On December 17, 1903, the Wright brothers made the first flight with a powered aircraft. Gliders have been flying longer than that.
All airplanes are aircraft, but not all aircraft are airplanes. "Aircraft" means any man-made thing that is supposed to be able to maintain sustained flight--gliders, helicopters, autogyros, blimps, paper airplanes, whatever. An "airplane" is a powered heavier-than-air aircraft with fixed wings.
They were powered by steam or diesel
There are no v-12 powered aircraft at present in the RAF
The very first airplanes were gliders.
diesel
The U.S.S. Enterprise, CVN-65, was the first nuclear powered aircraft carrier. A link is provided.
There were no powered aircraft. The first powered filght was in 1903 and the Wright Brothers.