General

International Airport: Myanmar has 3 international airports:
Mandalay International Airport: The airport is located 35 km south of Mandalay in Tada-U, and one of only three international airports in Myanmar. Since it was completed in 1999, It is the largest and most modern airport in the country. Services available at the Mandalay airport: currency exchange, shared and private taxi transfers, duty free shopping and dining.
Yangon International Airport: This primary and busiest international airport of Myanmar is located in Mingaladon, about 15 km north of downtown Yangon. The third largest airport in the country, after Mandalay International Airport and Naypyidaw International Airport.
Naypyidaw International Airport: This airport is located 16 kilometers southeast from Naypyidaw, the capital of Burma (Myanmar). In the past, before Naypyidaw was founded in 2002, this airport belonged to the nearby town Pyinmana. The airport was on 19th December 2011 officially opened.
Domestic airports: Besides the three international airports, and the project for a fourth one, Myanmar provides also the service of 45 domestic airports:

Air companies:

Myanmar National Airlines has been in operation since 1948 and is the national flag carrier of Myanmar. It has the most extensive route network within the country and has recently re-launched international for better services.
Several domestic airlines in Myanmar are: Air Bagan, Air KBZ, Asian Wings Airways, Air Mandalay, Myanma Airways, Yangon Airways,… In general, they provide services equal in price, equipments, food and schedule.
Vietnam Airline, Thai Airways International, Silk Air, Air Asia, Air Condor, Hong Kong Express,… operate flights from and to some big cities like Hanoi, Ho Chi Minh City, Bangkok, Singapore, or even Frankfurt.

Baggage regulations:

Baggage allowance on domestic flights is limited to 20 kg. A fee of maximum 3 USD per kg is charged for excess luggage but most of the time, if it is only a few kilograms extra, the airline waves this fee. Excess luggage can be left in Yangon hotels for collection on return from upcountry. Passengers are permitted one piece of hand luggage which should have a maximum length of 56 cm (22 inches), width of 45 cm (18 inches) and depth of 25 cm (10 inches) including all handles, side pockets, wheels etc. However, in practise these regulations are not followed properly.

Airport taxes:

The domestic airport tax (1000 Kyat) and the international airport tax (10 USD) are included in the air ticket and is not needed to be paid at the airport when checking in.

Arrival formalities:

After arrival at Yangon International Airport queue up at the immigration counters with a filled-out arrival card and your passport with your visa stamped inside. After passing immigration, collect your luggage from the luggage belt and proceed to the customs counter. Hand over your filled-out customs form to the officer. Note that mobile phones and laptops are no longer kept in storage on arrival as is still written in some guidebooks and websites.

Passenger’s declaration:

All Passengers bound for Myanmar will be required to fulfill customs requirements which are important pertaining to entry and departure. All arriving passengers will have to fill up the Passenger’s Declaration Form (P.D Form) CR(819).

Foreign exchange:

You may bring in as much foreign currency as you want. However foreign currency exceeding USD 10,000 or equivalent taking in by a foreigner must be declared on Foreign Exchange Declaration Form (F.E.D Form).
(a) Foreigners, taking in foreign currencies exceeding USD10,000, need to declare.
(b) Myanmar Nationals, taking in any amount of foreign currency, need to declare.

Note

– Do not forget to keep the FED Form. You have to surrender it to customs on your departure.
Any consignment for exportation of gems stones, set or unset, jewellery, silverware, handicraft purchased in Myanmar shall only be allowed against the production of special cash memo or voucher issued by the AUTHORISED DEALERS.

For more information about the formalities upon arrival, please have a look at the official website of Myanmar Customs:
http://www.myanmarcustoms.gov.mm/passengerdeclaration.aspx