Why doesn't my phone pick up the network automatically while roaming?

A

AC Question

why does phone not pick network automatically while roaming?

I travel within the country a lot by air. I usually switch off during flight travel and after landing in new city, switch it on again. When I do this, I find that I have to manually go to settings, search for all telephone networks and select my network so that I can start making calls again. However, with a lot of other people, I note that they have instant network access as soon as they land and don't have to do the steps I do. Is it something to do with the device or the network? How do I fix this?

Device used - LG G3; Network - Airtel; Country - India