By Rail
Assam is also well connected through Rail Services to Indian cities. Three major routes of North East Frontier Railways NF Railways covers entire Assam and provides linkages to principal zones and cities in north, east and south India. Guwahati railway station is the largest in Assam and is served by direct trains from most of the major cities in India. The Rajdhani Express fully airconditioned from New Delhi takes 27 hours and Saraighat Express from Howrah in Kolkata takes 17 hours are the fastest ones. There are many direct trains from Delhi including the Rajdhani Express and Kolkata for Dibrugarh in Upper Assam. Usually, Dibrugarh is an additional nights journey 12hrs from Guwahati. The trains offer beautiful vista of the countryside, although, one must take note that because of agitations in the state, it is advisable to avoid train travels as incidents of stone pelting on trains is well known and it happens in the area after Dimapur. If you must travel by rail, make sure that your reservation is in the air conditioned compartment as the windows are sealed.
By plane
There are good air-connectivity to Assam from the major cities in India. Guwahati's Lokapriya Gopinath Bordoloi International Airport is the businest in Assam and other major airports are in Dibrugarh, and Silchar. Air India and Indian Airlines along with several other private airlines operate daily services from all the major cities such as Delhi, Kolkata, Mumbai, Bangalore, etc. Moreover, there are other airports in Tezpur, Jorhat, etc with less frequent flights connecting cities such as Kolkata and other cities of North East Region. Arriving by plane, however, gives a wonderful welcome aerial view of the green valley surrounded by blue hills in Assam. The major airlines operating in the region are:
Jet Airways (http://www.jetairways.com/)
Kingfisher Airlines (http://www.flykingfisher....)
Indian Airlines (http://indian-airlines.ni...)
Jetlite (http://www.jetlite.com/jl...)
Spicejet (http://www.spicejet.com/)
Air Deccan (http://www.airdeccan.net/) now known as Kingfisher Red
Indigo Airlines (http://book.goindigo.in/s...)
For the international travellers from East Asia or South East Asia, the most easiest route to travel to Assam is via Kolkata. There are several direct flights from Kolkata to Guwahati, Dibrugarh, Silchar and Jorhat. Journey time in a direct flight from Kolkata to Guwahati is of less than 45 minutes, while to Dibrugarh the eastern most civil airport in Assam is of around 90 minutes. Similarly for travellers from Europe, Middle East, Central Asia and African countries either via Delhi and Mumbai or even Kolkata route is preferable. However, Delhi and Kolkata have higher frequency of flights to Guwahati. A Delhi-Guwahati direct flight takes 2:30 hrs of journey time. There is currently no direct flight from Guwahati to any international destination after cancellation of the Air India's Guwahati-Bangkok flight few years back.
MYANMAR citizens can come in thru the border post of TAMU-MOREH and take a connecting flight from IMPHAL to GUWAHATI. Also there is regular BUS service from IMPHAL to GUWAHATI. Specially , for taking MEDICAL TREAMENTs as Guwahati have a lot of high class HOSPITALs.
By car
There are highways from Indian states in the west and buses run between Siliguri to Siliguri buses are available from Kolkata, Darjeeling and Gangtok and Guwahati; However, travelling by bus may not be comfortable in this patch and travel time is usually longer than that of trains. Road connectivity to surrounding Seven Sister States is good, however may take different durations depending on the location of the state.
Tamu in western Myanmar is connected to a reasonably good highway to Assam via Manipur; Tamu in Myanmar border is closer to Mandalay. The historic Stilwell Road between Assam-Myanmar-China from Ledo in Upper Assam to Myitkina in Myanmar and further to Kunming in China is right now not fully operationalised.
There are also roads connecting Bhutan.