I'm about to visit India, and I will be on domestic flights on both Jet and AI. Their websites show that they have slightly different carry on size rules, and I'm also terribly confused about the laptop additional-carry-on rule. I'm hoping someone can give me clarity about what I can bring aboard.

AI says 22" x 16" x 8", Jet says 22" x 14" x 10". That 8" is a real killer, since many of the bags I can find are 22" x 14" x 9". If I have to hit 22" x 14" x 8", to meet both airlines rules, that's really small.

Also the rules say that I can bring a laptop on board, but they don't mention a laptop "bag". I assume I don't just hand-carry the laptop on board. In the US I usually use a backpack as a "personal item" in addition to a carry on item. What are the limits on my laptop bag?

Thanks for any help! This is so confusing.
-- Ethan