Comp As from each end and the middle
I never personally needed the Comp A system but have been involved several times:
Ark Royal (of "We are sailing fame") setting off on final voyage when young rating's father VSI in Derby. I was flying night circuits at Lyneham - did we have enough fuel for LYE to St Mawgan to E Midlands? Answer yes. rating in navy helo to StM, by us in Albert to EM where met by Army driver and taken straight to Hospital.
When in ASCOT Ops - 2 Comp A on the Tri* from MPA, one for Newcastle one from Belfast, Tristar inbound to Gutersloh. Hold 125 at Gut. Comp As whisked off Timmy first and straight into 125 and away. First one dropped at Newc ERO and on to Belfast. So even ASCOT Ops could get it right.
In similar vein was a premature baby at Akro, sent to Tel Aviv by helo with mother as outside the capabilities of Akro hospital. Few weeks later when baby still only weighed 4 1/2 lbs we had to send the Tri* to pick it up - very large aeroplane for a very small payload!!
And expanding it to another similar but Aeromed problem: Army Sgt on BATT in Kano, Nigeria, slipped in shower and banged his head causing blood clot. Aeromed needed but minimum airborne time for casualty specified. VC10 fired up for BZN - Dakar - Accra for night stop. This gave about 20 hours to get diplomatic clearances for the return from Kano direct to BZN over Niger, Algeria and Spain. Surprisingly the most difficult was Spain and the VC10 almost had to do a dog leg around Majorca but clearance came through with about 10 minutes to spare. Out of Gibraltar though aeromeds would regularly get direct routing across Spain even if we did not ask for it.
In all these cases almost everybody does pull out all the stops but sometimes achieving the desired result was impossible.