An aircraft moving at near Mach speeds has a significant amount of friction caused by air. It's not necessary for an IR system to be able to see the exhaust of

An aircraft moving at near Mach speeds has a significant amount of friction caused by air. It's not necessary for an IR system to be able to see the exhaust of an aircraft. In fact, all aspect IR missiles have been around since at least the AIM9L which was used in the Falklands War in 1982.