User blog comment:AntiScootaTwo/Call of Duty: Advanced Warfare confirmed to be set in 2054/@comment-5670680-20140503084707/@comment-3967954-20140503085653

Yes, they exist, but a). they aren't proven designs and b). they aren't necessarily intended for combat usage. No militaries currently have any interest in human-piloted mech suits, hover bikes, etc, and they probably never will. VTOLs are plausible, I guess. BOII was pretty down-to-earth when it predicted that the future of warfare is going to be largely drone-based, which it probably will be.

Think of it this way: Da Vinci had the designs for very early helicopters, tanks, experimental guns, etc way back in the 1500s. Were his designs fielded? No, because they weren't very practical. It would take another 500 years or so before tanks and helicopters were perfected. If mechs are going to happen (quite frankly, I can't see what combat situation they would actually be useful for), it'll most likely take centuries before they're perfected.