Until 1961, because of the lack of paved roads, travel in Bhutan was by foot or on muleback or horseback. The 205-km trek from the Indian border to Thimphu took six days. Modern road construction began in earnest during the First Development Plan (1961-66). The first paved road 175-km-long was completed in 1962 (a branch road later linked Paro with the Phuntsholing-Thimphu road). Described as a jeep track, it linked Thimphu and Phuntsholing with Jaigaon, West Bengal. The travel time by motor vehicle from the border to Thimphu had shrunk to six hours. Some 30,000 Indian and Nepalese labourers were imported to build the road with Indian aid at a time when India was bolstering its strategic defence against a possible Chinese invasion. Bhutanese also were obliged to donate labour for the construction work. Another road connecting Tashigang with Tawang, Arunachal Pradesh, also was built.
By the mid-1970s, about 1,500 km of roads had been built, largely by manual labour. There was a linked network of 2,280 km of roads in 1989; at least 1,761 km of these were paved with asphalt, and 1,393 km were classified as national highways. Despite the construction of surfaced roads linking the principal towns in the south, the mountainous terrain elsewhere makes travel even from one valley to the next quite difficult. Most roads run in river valleys. As part of the Sixth Development Plan, the Department of Public Works, in cooperation with the Indian Border Roads Organization, made plans to construct and upgrade 1,000 km of roads and to extend the road network through the five major river valleys by 1992. It was estimated, as part of the Fifth Development Plan, Bhutan also needed some 2,500 km of mule tracks to connect the nation's 4,500 settlements.
As of 2008, Bhutan did not have any railways. Bhutan and India have signed an MOU to connect Bhutan with the Indian Railways network. Further progress was reported in March 2006. On January 25, 2005, the Bhutanese King and Indian Prime Minister agreed to carry out a feasibility study for rail links. Possible routes are Hasimara-Phuntsholing with a branch to Pasaka (18 km); Kokrajhar-Gelephu (70 km); Pathsala-Naglam (40 km); Rangla-Darranga-Samdrupjongkar (60 km); and Banarhat-Samtse.
The single runway at Paro Airport is located in a steep-sided valley with restricted VFR approaches. During the monsoon season, flights are often delayed by cloud cover. Drukair is the national carrier, connecting Paro to Bangkok, Dhaka, Kolkata, New Delhi and Kathmandu. The airline replaced its two ageing BAe 146 four-engined jets in 2004 with faster and more capacious Airbus A319-100 aircraft.
The Royal Bhutanese Government's five year plan (which covers 2008-2013) includes the building of at least two more domestic airstrips at Bathpalathang in Bumthang District and near the southern Bhutanese town of Gelephu in Sarpang District.
Airports - with paved runways :
1,524 to 2,437 m: 1 (2010)
Airports - with unpaved runways :
914 to 1,523 m: 1 (2010)
total: 8,050 km
paved: 4,991 km
unpaved: 3,059 km (2003)