You can climb to 30K with about half your fuel, then glide for a considerable distance.  It only takes a few seconds of re-igniting the motor to regain the lost alt, then rinse and repeat.  The main problem is, it takes too long to re-ignite the motor.  This was an instantanious ignition, but is modeled like turbines with a spool-up period.  Also, you can keep the "candle" lit, but just pull the throttle all the way back.  It still burns fuel, but much more slowly.  I had no problems landing it off line, but that might not be the case if you're trying to set it down at a field under attack.  Finally, to prevent people from using it, just kill one fuel tank at their base.  This drops the available fuel at that field from 125% to 100%, making drop tanks unavailable.  Due to a modeling oddity, the 163 is treated as if it has drop tanks. Disabling drop tanks at their field disables 163 there as well.