How long is the flight — and is there another way in?
A direct Bangkok–Chongqing flight takes about 3 to 3.5 hours, depending on the winds and routing on the day — a short, easy hop. Thailand and China share the same time zone, so there is no clock change and no jet lag. Full-service flights include a meal and baggage; on a low-cost flight, especially as a family or with heavy bags, it pays to buy your seat and baggage allowance when you book (far cheaper than paying at the airport).
Beyond flying direct into CKG, Chongqing also has a very convenient overland route by high-speed rail from Chengdu — so if direct tickets are pricey or do not match your dates, consider flying into Chengdu and taking the train, getting two cities in one trip.
The main, fastest way, with direct flights on several airlines from both Suvarnabhumi and Don Mueang. Land at CKG Terminal 3, then take Metro Line 10 or Line 3 straight into town. It suits almost every trip — the only things to watch are checking your terminal and the rush-hour crush on the metro.
Chengdu has more frequent flights from Thailand than Chongqing. If direct CKG tickets are expensive or sold out, consider this: land, then take a high-speed train into Chongqing North (重庆北). From Chengdu East it is as quick as about 62–75 minutes, with dozens of trains a day. You get Chengdu — the panda city — thrown in, just allow time to get from the airport to the railway station.