Car wash guy is good. Why does everyone have such bad teeth?

Slightly more responsible than the guy knocking one down with a sledge.

Old school saber fights aren't as "flashy" as the new ones, but oh so more satisfying.

"It feels like a .....pointy stick." Geez....

The mission generally dictates the engineering and design of a mechanical system. The Buran and the Shuttle are prime examples. The new X-37 resembles both in general shape because a reusable "space plane" needs certain specific physical characteristics.

The Mig-25 looks like the F-15 because both were originally designed as high altitude, high mach interceptors. The demand placed on the system by the overly large engines dictates the shape.

The basic principles of radar "stealth" dictate certain shapes to be effective. The Have-Blue shape was effective against high frequency radar through deflection. As materials technology advanced, e.g. radio absorbing materials, more aerodynamic shapes could be implemented and still retain "stealthy" characteristics, if not improve upon them.

All the F-22 vs Pak50, M1a1 Abrams vs T80 videos are funny. The 1 versus 1 advantages are fun to debate, but its the entire system that wins or loses the fight. In the same vein, its common knowledge that German armor in WW2 was vastly superior to American armor in every technical way. Similarly, German fighter aircraft were more maneuverable than the P-47s and P-51s that they fought. Unfortunately for the Luftwaffe, this superiority was not enough to defeat the allied system as it rolled east across Europe.

The term 5th generation does not define the aircraft themselves, but the system they belong to. If you read wikipedia, this does not mesh, but the wiki values maneuverability (which is inherently limited by the pilot), stealth features (limited by current materials and design), advanced avionics (what does this mean?) and multi-role capabilities (we have had this since the 1980's). The key to 5th generation fighters and its defining characteristic is the ability to integrate the new fighters with every other piece of war equipment in the theatre, not just in tactical use, but the total meshing of sensors and 2-way data links. Its the difference between a war of attrition and a war of "look first, shoot first".

The Russians appear to be building an excellent stealth fighter that looks sexy as hell. The Chinese are doing the same. What they both lack at the current time is the "backend" systems to make these new 5th generation-esque vehicles fully capable. The Pak50 and the J20 won't be sharing targeting data with their Navy or other ground forces anytime soon.