For Jet, the Jet HDFC Diners card is the best out there.. with its earn ratio, both for jet transactions and other transactions, bonus miles and tier points etc.

For AI, the SBI card was the best, even with the mile redemption devaluation that AI had few months ago. But with the bonus deval announced two days ago, I personally am going to cancel this card.

If you can, get both HDFC Diners Black and HDFC Diners Jet

But then I fly a lot with Jet and have plat status with Jet and gold with AI (via the sbi card)