Since Crete seems to be coming up a lot, here is maybe the best source I have found on it:
It basically includes analysis of the operation by various allied intelligence agencies and officers after the fact. Its pretty comprehensive and includes what they knew (a surprising amount by the time the reports were created) about the German preparations, deployment and equipment, the same for the Allies and what went wrong, including lessons for next time.
The Problems with Crete go beyond armoured forces but it was also a close run thing, so a few armoured forces may make a difference. Hopefully you find it useful.
Having checked the source I posted earlier, I found this on the German airfield deployment:Before we get to Crete, there is still Greece. The attack on Crete depended on having sufficient airfields within range of Crete. IIRC most of those for the fighters and some of those for the transports were on Greek islands between the mainland and Crete. I believe Rhodes was used as well. If the Germans suffer heavier losses in Greece, and the Allies (including the Greeks) less, it might be possible that some of those airfields are not available, or not available in time. Likewise if the occasionally mentioned idea of invading Rhodes goes ahead before the fall of Greece (which I think is unlikely, but still) then there is one less airfield available and one more priority for the Axis to try and take.
Fighters and dive bombers used newly constructed landing fields on the southern PELOPONESE and airdromes at MOLAOI, MILOS, CORINTH, ARGOS, SCARPANTO. Transport planes cane generally from the ATHENS-CORINTH area; some came from SEDES and MIKRA airports at SALONIKA. Long-range bombers took off from airdromes in the vicinity of THEBES and SALONIKA. Italian bombers from RHODES and German bombers from SICILY operated against shipping.
Molaoi, Corinth and Argos are all on the mainland, and unless the British can do significant damage to them in the retreat, they are likely to be available. Scarpanto was in Italian hands before the war. Milos was a Greek held island, but I don't know how feasible denying it to the Germans would be. I can't find any references to Allied troops there prior to the German invasion.The final disposition of aircraft in preparation for the attack was as follows:
Germans Dive Bombers: MOIAOI, ARGOS, CORINTH, SCARPANTO, MILOS
Single-engine fighters: MOLAOI, MILOS, CORINTH, ARGOS
Long range fighters: ARGOS, CORINTH and ATHENS area
Long range bombers and recce.: ATHENS (ELEUSIS and MENIDI), SALONIKA (SEDES and MIKRA), BULGARIA (KROMOVO and PLOVEIV), RHODES
Transport aircraft: ATHENS (ELEUSIS, MENIDI), MEGARA, CORINTH, PERIVALI, TANAGRA, TOPOLIA, SALONIKA (SEDES and MIKRA).
Eleusis (and presumably Menidi) was used by the RAF, and I think that it was captured by the Germans intact with all fuel and stores. If it is properly destroyed in the retreat (possibly with the explosives taken off the Clan Fraser) that could inconvenience the Germans a little as they repair it. I am not sure it would do much to delay the operation to Crete though. Even taking Rhodes doesn't seem like it would significantly torpedo the operation if the Germans decide to go ahead with it.