Questions have been raised about the long-term future of Cardiff Airport after a budget airline's decision to halt operations there.
Air lobby group Wales Air Network said Cardiff was on course to become the size of a smaller regional airport, such as Newquay in Cornwall.
Bmibaby said on Wednesday it was pulling out of Cardiff in the autumn.
An airport spokesperson said it was looking forward to forging new relationships with other airlines.
Peter Phillips, chairman of Wales Air Network and a former head of marketing and communications at Cardiff Airport, said: "It's approaching [the passenger numbers of] Bournemouth [airport] already and it's on the way to Newquay.
"This should be a capital city airport up against Edinburgh and Belfast."
Mr Phillips, a non-executive director at Pembrey Airport in Carmarthenshire, said the airport needed to engage with the travel industry and business community and start competing again.
David Rosser, director of business group CBI Wales, said help was needed in securing new routes.
"I think we need a real concerted effort from the assembly government to help the air operators to find new operators for new routes," he said.
"We need international air links out of south Wales."
Bmibaby, which employs 69 people at Cardiff, blamed the economic climate for its withdrawal, saying it would focus on airports with strong growth opportunities.
The airline started operating out of Cardiff in winter 2002.
Airport managing director Patrick Duffy said: "It's not a question of saying no to Wales, it's a question of consolidating their fleet... which is getting smaller and smaller every year anyway.
"This has been predictable for three or four years and in that time we have been contemplating what life would be like without them."
The total number of people using the airport fell 14% in 2010 to 1.4m, down from 1.6m in 2009.
But some transport analysts said the airport could use the loss of bmibaby as an opportunity to attract other airlines.
Prof Stuart Cole, from the University of Glamorgan, said: "Cardiff Airport has gone through positives and negatives over the years.
"It reduces the number of choices for people flying from Cardiff, but there are other operators and other operators could come in."
He said the assembly government was introducing an airport bus service and planning rail improvements which "would make Cardiff far more attractive than Bristol".
Martin Evans, of the Wales Transport Research Centre of the University of Glamorgan, said bmibaby's decision did not mean the end of Cardiff Airport.
"It's still going to be the case that large numbers of people in south Wales will want to travel to the southern Spain resorts," he said.
Meanwhile, the airport has been boosted by a commitment from airline Flybe
Mike Rutter, chief commercial officer, said: "Flybe is, and remains 100% committed to Cardiff Airport and we will provide extra capacity where necessary on the routes that we currently operate where bmibaby have withdrawn.