The number of people jetting abroad on holiday could fall sharply if they had to board pilotless planes, a survey by financial services firm UBS suggests.
More than half the 8,000 people asked said they would be unlikely to take a pilotless flight, with only 17% saying they would board such a plane.
Boeing plans to test pilotless planes in 2018 and UBS says airlines could save more than $26bn (£20bn) in costs.
UBS added that plane travel would be safer, but safety experts disagreed.
Steve Landells, the British Airline Pilots Association’s (Balpa) flight safety specialist, said: “We have concerns that in the excitement of this futuristic idea, some may be forgetting the reality of pilotless air travel.
“Automation in the cockpit is not a new thing – it already supports operations. However, every single day pilots have to intervene when the automatics don’t do what they’re supposed to.
“Computers can fail, and often do, and someone is still going to be needed to work that computer.”
UBS said that its projected savings for airlines would come through cutting pilot costs. It added that the business jet industry could save up to $3bn and civil helicopters about $2.1bn by introducing pilotless aircraft.
More than $3bn would also be saved in lower insurance premiums and there would be chances of extra revenue from increased numbers of cargo and commercial flights.
However, the savings could pale into insignificance if the numbers of people travelling by plane dropped.
Of the 54% of people who said they would be very unlikely to set foot inside a pilotless aircraft, the older age groups were the most resistant with more than half of people aged 45 to 54 shunning the idea.
The younger age groups were a bit more receptive, though, with the 25-to-34 age group most likely to give it a try (30%).
While flying is generally regarded as one of the safest forms of travel, the UBS report suggested that pilotless planes would make it even more secure.
It found that around 70% to 80% of the accidents that do occur are the result of human error, with crew fatigue responsible for 15% to 20% of those.
It is also clear that if pilotless planes were to become the norm, then military levels of security both inside the plane and in communications would be vital.
Acceptance of the concept would also be crucial to its success.
Jarrod Castle, UBS’s head of business services, leisure and travel research, told the BBC: “It is a question of public perception and people being comfortable with the idea.
“Clearly a seven-hour flight carrying 200 to 300 people would be the last part of the evolution but we also feel that machines can gradually take over and then reduce the number of pilots in the cockpit from two to one over time.”
Céline Fornaro of UBS added: “The smaller the plane and amount of passengers, the more realistic it is to see this.
“It is not just our view, companies like Airbus are trying to get into this world where you could have small helicopters carrying two or three people unmanned.”
Air transport consultant John Strickland believes pilotless planes could definitely become a reality, as long as certain hurdles are overcome.
“It is conceivable but would be some way off in the future,” he told the BBC. “There would have to be an overall focus on safety and there would be a psychological barrier to get over to win the public’s trust.
“We step on monorails at airports and travel in some driverless trains and cars, but the whole psychology of being in the air and not having humans at the front is quite a challenge.”