At best with a full load like these have, the MiG-21 only had an hour of flight time on full tanks at cruise speeds... short range was a flaw shared by most Bomber Interceptors designed in the 50's and 60's on both sides of the Cold War... range was traded off for speed and time to altitude ability...

If I was going to add the Afterburner flame, I'd have to depict the MiG's after the attack when they'd dump in extra throttle and head for the deck to avoid that angry response of the Bomber Escorts... Usually F4's (though others also served as escorts for the Bomber raids in 'Nam)...

Most of my Aircraft pics don't use an afterburner effect since it wouldn't suit with the reality of the aircraft in flight... I was tempted, but chose to add the heavy exhaust plume instead as it was more accurate to the situation...