WRT the Estonian airspace interception story, the MiG-31 sounds like it's the ultimate of a 1950-1960s mission-concept, ground-controlled interceptor, whose target is fleets of bombers coming in at high altitude for a nuclear attack. An interceptor was/is very fast, climbs fast, and can operate at very high altitude. BUT maneuverability is sacrificed and its range of weapons tailored to its interception role.
That bomber strategy was largely abandoned by the US in the 1970s (maybe earlier, given the abandonment of the B-70 program), and the USAF's last interceptor was the F-106. The USAF went largely multirole as it evolved the F-4 Phantom. The USN did similarly, though the F-14 Tomcat started out with interceptor being one of its primary missions (the Phoenix missile was more suited to bomber targets rather than maneuvering fighters).
