You can reach here very easily by air from anywhere of the world. In the country there are two international airports and many airlines operating here.
You may visit any airlines when you are planning. Main International airport of Bangladesh is Sha Jalal International Airport. It is in central point of Bangladesh. So from any where you may come to Dhaka.
There are a lots of airlines are operating in Bangladesh, some are written below.
Biman Bangladesh Airlines
Chaina Eastern Airlines
Chaina Southern Airlines
Pakistan International Airlines
Royal Bengal Airlines
Saudi Arabian Airlines
Thai Airways International
Also some other airlines are operating in the country.
Before you come here, check with your airlines about your flight details and related information.To get a visa you should contact Bangladesh High Commission in your country with necessary papers and a valid passport. By visiting their website you can have gather information also.