PAF pilots would fly F-16 Block 60/61 from UAE in the event of an Indian invasion of Pakistan. They could also fly J-10B from China given J-10 is very similar to F-16. China would likely deploy over 100 J-10B and Flankers in Tibet for offensive operations against India and deploy another over 100 J-10B and Flankers to Pakistan like how the US 8th air force was deployed to England for operations against the Third Reich. Therefore, if India invades Pakistan, the most potent opponent of the Indian air force would be the Chinese air force rather than the Pakistan air force. Luftwaffe was destroyed by the US air force deployed in England and the RAF. It is unlikely the Indian air force can best the combined Chinese and Pakistani air forces.
The eastern front would pit InAF against PLAAF stationed in Tibet. The western front would pit InAF against combined PLAAF and PAF and possibly other Muslim air forces in Pakistan like how Luftwaffe fought against the American and British air forces stationed in England during WW2.