More confusion over whether Newcastle Airport was in line for a share of a £20 million fund to help it develop new routes followed a statement from Ministers that they must ask the European Commission for permission to hand over the cash.
But she said: “It would have been better to have got the policy right in the first place than trying to fix it now.”
It follows Chancellor George Osborne’s announcement in the Budget earlier this year that a £20 million Regional Air Connectivity Fund would be made available for airports outside the planned high speed rail network to help them attract airlines and launch new services.
This raised hopes Newcastle Airport could secure its long-held ambition of providing regular trans-Atlantic flights.
But it then emerged that only airports with less than three million annual passengers would be eligible for the assistance - while Newcastle currently serves around 4.7m each year.
The airport asked local MPs to help it secure a share of the fund.
And Ministers have now said they hope to ensure airports with fewer than five million passengers are included, but only if the EU agrees.
Speaking in the House of Commons, Ms Onwurah, MP for Newcastle upon Tyne Central, said: “Newcastle airport grew its freight from £20 million in 2006 to £250 million last year, mainly on the back of the new Dubai route, but because it attracts more than 3 million passengers per year, it cannot have access to the regional connectivity fund.
“So what is the Minister doing to bring new routes to Newcastle and improve the economy?”
Transport Minister Robert Goodwill told her: “I was pleased that the Chancellor announced the regional connectivity fund. When I was at Newcastle airport in February, there was excitement about that. It is also looking to serve further routes.
“Although the limitation is for airports of fewer than 3 million passengers, there is a provision under exceptional circumstances to allow airports such as Newcastle with fewer than 5 million passengers to participate.
“We are having conversations with the European Commission to ensure that we can do something and that we do not breach any state aid rules.”
Ms Onwurah said: “I thought he was desperately scrabbling to come up with a reasonable policy having realised that they made a mistake by excluding important regional airports like Newcastle from the means to help them grown.
“His reply was helpful but it would be much better if the scheme had been well thought through in the first place.”
The Commons Transport Committee has launched an inquiry into the role played by smaller airports.
It is to look at the strategic importance of smaller airports and the extent to which they meet the needs of regional economies.
The inquiry will also consider whether the Government is doing enough to support smaller airports.
And it will look at whether councils and local enterprise partnerships could do more to back smaller airports.
Written submissions can be provided to the inquiry by Friday 3 October 2014 through its website at www.parliament.uk/transcom .