PAF was a miserable failure in 1971. The Pakistani security doctrine was based on premise of 'the defence of East lay in the West' i.e. to say, in case of hostilities with India regarding East Pakistan, the major Pakistani defence forces would be concentrated in West Pakistan and make major territorial gains in Kashmir-Punjab-Rajasthan belt, to negotiate India to a truce and hence safeguard East Pakistan. Unfortunately for Pakistan, this did not happen. India was able to fight West Pakistan to a stalemate, while making the blitzkrieg in East-Pakistan. India had learned valuable lessons form the 1965 war. The main lesson was that India was able to repulse any attack in Kashmir-Punjab-Rajasthan sector, which enabled them to plan the blitzkrieg in East-Pakistan. Pakistan seemed to not have learnt any lessons from 1965. They employed the same military tactics they has used in 1965, and Indians were prepared for it.
The war in West-Pakistan was supposed to be spear-headed by PAF,since it was the relatively stronger arm of the Pakistan military, but it failed very miserably to support its ground forces in gaining territory on the western border. The battle of Longewala is a prime example for this. Instead of being the offensive force, PAF operated as a defensive force for most of the war. On the other hand IAF gave full support to the ground forces and was very instrumental in the success of India in 1971 war. Not to mention IN's role too, especially in executing a effective blockade of East-Pakistan and hammering of Chittagong port by IN's air wing.