Or better launch this aircraft with a ZEL rocket launch configuration from even frontlines. Intercept the enemy aircraft and return back landing somewhere inside in a protected airfield.Another option for a stop gap measure against jets would be to use a ramjet-a2a-drone capable of mach 3 with a wing configuration similar to one below. It needs to be upgraded to carry inside at least 2 a2a wvr missiles or if possible larger bvr missiles and it needs to have a radar inside the nose cone. This one is launched from B-52s but jettisonable rockets can be used to give the initial speed for the ramjet for ground based launch. No need to develop-install the expensive jet engine and no moving radar reflector parts in the engine being a ramjet. It would be easier to produce in numbers.
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Jet engine low rcs a2a drones would have a longer range and can carry more payload but they are in development stages in most countries. But since sams and direct radar lock is an immediate give away of ads-radar own position that leaves air to air engagement as the remaining option and doing this as cheaply and effectively as possible becomes the main issue.
You will need at least 2 strong rockets attached parallel under its wings though to make D-21 reach its required speed and altitude to activate the ramjet.