As Takao has pointed out, it was one squadron assigned to Force Z. As for quality, the Buffalo did not have a good war, particularly in the Far East so its performance for the Finnish airforce may well have more to do with the respective merits of the pilots available, and we do know the Japanese were good at this time.There were planes enough in quality and also in quantity.
It would have been interesting if Phillips had placed a call for air support when the Repulse reported an aircraft shadowing the force at 0630 hrs. or immediately upon hearing that the destroyer Tenedos was under air attack around 1000hrs.
Maybe, but Phillips was the wrong man for the job and unlikely to make such a call, convinced as he was of the ability of his ships to survive and of the need to keep radio silence. My guess would be that Force Z would take significant damage, but even though its unlikely the crippling hit on Prince of Wales would occur - freak hits are just that - any major damage would be enough to finish Force Z as a threat, and simply become a matter of salvaging two ships that should never have been so badly risked.That incident should have made Phillips to react and called the pre planned air support.
Phillips was far from the only officer afloat to think capital ships would survive air attack, but he was also inflexble and had showed himself unwilling or unable to adapt in the past. A good enough officer for the previous wars, like so many before and after.
The RN had done its best to throw away all advantages during WWI by insisting on rigid radio silence, it had almost religious standing then, and had many officers convinced this war was to be fought the same way. To be fair, Britain did make very good use of radio intercepts on a strategic scale, so tended to place too much value on not allowing the enemy any such breaks even if it were to cost them a tactical advantage.Yes, what's the use of radio silence (if that was the reason for not orderding air support) after that?