Thousands of travellers to Nigeria are facing at least six weeks of severe disruption while Abuja International Airport is closed for runway repairs.
Flights are being re-routed to the city of Kaduna, raising security concerns and adding hours to passengers' journeys.
Many international airlines are also refusing to fly to Kaduna.
The cutting of direct flights to Abuja, an important business hub as well as Nigeria's political nerve centre, raises economic and security concerns.
Passengers will take the journey of around 160km to the capital on guarded buses, along a road where kidnappings have taken place in recent years.
Despite the ongoing work, a flight carrying passengers on Ethiopian Airlines, the only international airline that has said it will use the alternative airport, arrived at the new terminal at 11.30 local time (10:30 GMT), said a senior airport official.
"Airport staff were very cooperative but I think the systems are not ready. The systems should be ready," said one passenger.
Bismarck Rewane, a leading Nigerian economist, has said the closure of the airport in Abuja, where the government and central bank are based, will have a "catastrophic" effect on Africa's biggest economy.
It comes amid a downturn in the OPEC member which, reeling from low oil prices and militant attacks on oil facilities in its Niger Delta energy hub, saw its economy shrink 1.5 percent in 2016 - its first full-year contraction in 25 years.
Airlines including British Airways, Lufthansa and South African Airways have refused to fly into Kaduna owing to security concerns.
Kaduna airport has primarily been used for domestic flights, with Abuja airport handling 4,859 domestic flights in December 2015 - the last month for which figures were available - compared with the 171 that flew in or out of Kaduna.
Source: Reuters news agency