Well I work on aircraft. Yes they use alot of epoxies. Now with that said when epoxies are used they are used with rivets, bolts or screws. I have seen alot of adhesives disbond even with good prep work. Also aircraft are inspected daily and very periodically for structural disbond due to the environment and high performance nature.
In aviation NO ONE would use epoxy to bond aluminum to aluminum to hold fuel to 600 degrees. If you get a leak at 600 degrees there are fuels that will auto ignite at that temperature. Needless to say that isnt safe.
Its not that adhesives couldnt do the job its that welding or brazing is MUCH safer. When it comes to fluids everything in aviation is welded or brazed because it wont leak at extreme temps, high vibration and pressures. Adhesives are not the proper application for fluids especially fuel.