Kuala Namu International Airport is a new airport under construction to replace Polonia International Airport, inappropriately located in the centre of Medan City and with a difficult takeoff path and short runway. Construction began on 29th June 2006, shortly before the first anniversary of the crash of Mandala Airlines Flight 091. The airport is due for completion in 2009, and it will serve the city of Medan on the island of Sumatra, Indonesia. The airport will cost at least 4.4 trillion Rupiahs to build or approximately US$ 473 million, using the August 3rd, 2007 exchange rate.

Construction had previously been promised, initially in 1992, following previous crashes and safety concerns (construction was shelved following the Asian monetary crisis), but the airport looks like it will now go ahead. The plan is described in, whereby the airport would be located 20 km North East of Polonia airport, 3 km from the sea and on a site of area 6.5 x 2.1 km. The new airport will offer greater safety and capacity, with a Phase 1 (2010), first year of operation plan for 6.4 million passengers, of which 5.1 million would be domestic, 1.2 million international and 0.14 million international transit passengers. By Phase 2 (2025), the airport would be servicing 14 million passengers, 2.5 million international and 0.63 million international transit passengers.

The airport will be Indonesia's second largest, following Jakarta's Soekarno-Hatta airport and will eventually have capacity of 50 million passengers, a figure if realised today would place the airport in the top 10 busiest by passenger numbers in the world, although by the time this figure is ever achieved it is likely that there will be many airports carrying more passengers.

Airside facilities would be controlled by the Indonesian government, while landside facilities would be owned by a joint venture (with PT Angakasa Pura II) company, which is expected to provide US$ 350 million initial investment, in return for a 30-year lease, after which ownership would revert to PT Angkasa Pura II. The airport will be linked to the city of Medan by a US$ 215 million railway project.