It is hard to see planes looking a lot different to how they do now. Sure, the structures, engines and electronics will evolve but the shape of an aircraft is largely controlled by aerodynamics and that is a pretty well understood science. Concorde apart, the shape of airliners hasn't changed much since the Boeing 707. Fuel costs, sonic booms and environmentalism will stop most airliners getting faster and passenger resistance will prevent blended body flying wings becoming popular. A hypersonic, edge-of-space type airliner might be something that could have a radically different look though.
It's the same with military aircraft, the F-22 isn't vastly different to an F-15 to look at despite the stealth, the Eurofighter has echoes of the Saab Viggen and F-16 and so on. Even odd looking planes like the B-2 have been done before (Horten, YB-49 etc.) The latest transport aircraft and helicopters all look much the same as their predecessors. UAVs have some scope to look different but even most of these have echoes of previous manned designs as well.