Ukrainian start-up carrier, SkyUp Airlines, delayed the start of its operations until early May 2018 due to the certification audit of the company, according to chief executive Yevgeny Haynatskogo.

"The new Ukrainian SkyUp airline plans to receive the certificate of the operator, allowing it to carry out flights in the first week of May and not in April as previously planned," he said in a statement.

The airline's two ex-MAS B737-800s on lease from Boeing Capital Corporation are already registered in the Ukraine, with a third B737-700 to follow from an undisclosed lessor.

SkyUp and Boeing previously announced a firm order for five B737 MAX aircraft — two MAX 8s and three MAX 10s — in deal valued at US$624 million at list prices. Delivery planned for 2023. Deal also includes five options also to be delivered in 2023.

SkyUp initially intends to operate charter flights from the Ukraine, with scheduled flights to follow soon thereafter.