There is no such thing, so the old saying goes, as a free lunch. But there may soon be such a thing as a free flight, at least according to controversial Ryanair CEO Michael O'Leary.
The very public face of the low-cost airline has long been renowned for outlandish statements, including the suggestion that passengers might be charged to use toilets on his planes.
So his claim that Ryanair could be charging customers nothing for a ticket within the next half-decade is sure to raise a few eyebrows - and cause a few shrugged shoulders.
But Mr O'Leary is adamant that the policy is possible.
"I have this vision that in the next five to 10 years, the air fares on Ryanair will be free," he said this week in a speech to the Airport Operators Association conference in London.
"The challenge for us in the future is to keep driving air fares down."
Instead of making money at point of sale, Ryanair would turn a profit by striking deals to receive a portion of the cash spent in airport restaurants, bars, cafes and shops as a result of its flights delivering people to, and picking them up from, busy terminals.
This would create a scenario, he argues, where "the flights will be full, and we will be making our money out of sharing the airport revenues - [and making money out] of all the people who will be running through airports, and getting a share of the shopping and the retail revenues at airports."
This vision would require an end to Air Passenger Duty (APD), the extra charge which, in the case of the short-haul services operated by Ryanair, can add between £13 ($23) and £78 ($138) to the cost of a flight ticket.
But abolition of - or a significant reduction in - APD would bring free seats a little closer, he believes.
"At many airports I'm paying more than £20 already with APD and fees," he told the conference. "If I start getting that back, why not? I'm doing seat sales this week at £4 and I'm paying the £13 APD - I'm paying you to fly with me."
His confidence does not stretch to the thought that major international airports will suddenly be willing to share their income from food, drink and duty-free purchases with airlines - but says he can envisage smaller hubs, keen to boost their passenger numbers, buying into his idea.
"I think it will happen," he added. "It just won't happen at Heathrow or those big hub airports."
"But [for] most of the other airports who are looking for big traffic growth, that process is already starting to happen, lowering airport fees and some of the charges."
Whether or not his plan would survive the UK announcing a so-called "hard Brexit" from the European Union remains to be seen.
Earlier this month, Mr O'Leary suggested that a total cutting of ties between London and Brussels would spark a rise in ticket prices.
"A hard Brexit would push up air fares," he declared.
"What is inevitable is that there would be less capacity in the UK - and that means higher prices."
Last year, the average price of a Ryanair flight was €46 ($69), including checked baggage.