Any recommendations for powerbank? my primary use case is iphone plus airpods. Prefer lighter ones. Also is there any limit of power( like 10k mah or 20k mah) in domestic and international flights ?

No limit. I use an Mi Power Bank which is small and has 22.5 W charging. https://www.flipkart.com/mi-10000-mah-power-bank-22-5-w-fast-charging/p/itm5ee8345d6a413

@witty-air-63049 how much time does it take to charge fully ? and in one charge how many times can it charge your phone ?

Depends on what charger you're plugging it into and how big your phone's battery is? I charge the power bank overnight so I'm not sure exactly how long does it take to charge.

hmm okay. Thanks.