I'm traveling to Delhi from Chicago next month via Air India (AI126 - Non Stop). As I need to carry baby food - which is really heavy - I'm planning to use a shipping box. I'll be getting a Heavy Duty box in size 18x18x16 (Which I believe is within the 62 inch limit by AI).

My question is; is there any restriction on using such boxes as checked baggage? I'll be keeping it under allowed 50lbs. Also, my connection to ORD is through Delta. Will they allow it for through check-in?

As many of the food items are in small glass bottles, I hope a heavy duty shipping box with enough packing noodles is sturdier than a cheap luggage bag/ duffel bag.