Years of uncertainty if Britain quits the EU, warns Ryanair's O'Leary
Ryanair boss Michael O'Leary has warned of years of confusion for business if the UK votes to leave the European Union.
Investment would be delayed or moved elsewhere if that happened, he said.
"There is no doubt if the UK leaves the EU for that three or four year period where they are negotiating to stay in the single market, there will be uncertainty.
"We - as a big investor in the UK economy - will invest less. Other big firms who want to invest in the EU will not invest in the UK, they will put those investment in the Republic or Germany."
He was speaking at the launch of new Ryanair services from Belfast yesterday, where he called on Stormont to do more to help airlines.
Mr O'Leary said scrapping air passenger duty in the UK was "the only way forward".
He also wants Stormont to do more in order to help create new routes and attract airlines.
"I think Stormont needs to mobilise... the Northern Ireland tourism industry suffers because there is no travel tax in the Republic, and there is a very mobile, porous border.
"A million people a year are travelling from Northern Ireland to Dublin to get lower fares that have no travel tax," he said.
The new routes - which will begin this winter from Belfast International Airport - will include Berlin and Krakow, alongside popular sun destinations such as Malaga and Tenerife.
The airline is also increasing the number of Belfast to London Gatwick flights to five a day.
He said additional routes could follow later ths year.
"I hope later in the year we will be returning and announce that a fourth aircraft will be based here... and some more exciting routes to announce as well."
He said he was now plugging Belfast's 'premier' airport, snubbing Belfast City Airport, which the airline pulled out of in 2010.
The airline is investing $300m (£212m) in three new planes, and said it would create 750 jobs.
The new hub will begin flights to London later this month.
And he reitereated his firm opposition to the UK leaving the EU, which he says "there is no upside to".
The Belfast launch came as Ryanair reported record passenger numbers for February.
It carried 7.4m passengers last month, 28pc more than in February last year, thanks to more and fuller aircraft.