There are worries that a flight path to test pilotless spy planes could be created across mid Wales.
The RQ-1 Predator spy plane was developed in the 1990s
In May it was confirmed that a £21m centre for developing the 'flying robots' would be established in Aberporth, Ceredigion.
Those living there and in Sennybridge in Powys are concerned a corridor could be created between the two towns to test the planes - known as unmanned aerial vehicles - posing a danger.
But a spokesperson for the cross governmental group behind the project said safety would be the "priority".
As many as 230 jobs have been promised in the short term as a result of the project, with the Welsh Development Agency saying 1,000 jobs could be created in 20 years.
It aims to turn Parc Aberporth into a centre of excellence for developing the planes - which are part of an industry already estimated to be worth £1bn.
But those living near and around the new project are worried about the UAV's being allowed to travel to Sennybridge for more rigorous testing.
One man from Lampeter said he thought living in the flight path could be "dangerous".
"They are unmanned and in their experimental stage as well, god knows what's going to go on. They may crash anytime."
Another woman said there were a number of farmers in the area and livestock could be at risk.
"It's quite frightening and I would worry but if this is what the future holds maybe we just have to put up with it."
Roger Williams, the Liberal Democrat MP for Brecon and Radnorshire, said that although he welcomed the investment in the area, he was concerned.
"I'm certainly upset that this is the first I've heard of it, and as I understand, none of the local authorities have been consulted either," he said.
"It seems to me that some of the preliminary work could be done over the sea rather than over the land, which it seems to me would be safer.
"I would have to know what the risks are, the size of the planes, and past history of any accident that has occurred."
The planes cameras and radar are used to gather intelligence during warfare or routine espionage without risking the lives of pilots.
Nato has also used them recently in Kosovo as tank-busters.
Donald Booth, from the Defence Diversification Agency, said the air corridor was a "long term aspiration", but said safety would be a priority.
"Any proposals to use them in civilian air space have to meet very stringent safety regulations," he said.
"There would be huge amounts of safety work done on how safe these things would be, what they would do etc.
"They are very safe by design and mostly very small. And they are operated by ground controllers," he added.
The Ministry of Defence was unavailable for comment.