I just transited MAA yesterday after having arrived on BA from LHR at 1:00 AM and departed for COK at 6:30 AM. I was first off the BA flight and exited Customs and Immigration in about 10 minutes. Long lines formed at immigration after me. The walk from international to domestic is all of about 1-2 minutes.

Have some insect repellant with you as there are mosquitos in the waiting areas even though the area is airconditioned. There was plenty of seating available. There was free WiFi connection available on one of the two public hot spots I found. The free connection helped me while away the time and catch up on old FT threads.

At the domestic terminal there are two waiting areas; the first one is immediately to the right after you enter the domestic terminal and that is where you wait until the check in process starts at around 4:00 AM. Then take you luggage for X-ray screening in the second waiting area which is to the left after you enter the building. There are no restaurants open in the wee hours of the morning so be sure to have some bottled drinking water with you. The security personnel will not allow you into the checkin area until around 4:00 AM when the various checkin counters open.

If you don't get a convenient flight to DEL you can check into the Trident Hilton which is just a mile down the road and they will provide a free airport pickup.