Two airlines are toying with the idea of having passengers stand up on flights.

Ryanair, the low-cost carrier airline based in Dublin, Ireland, and Spring Airlines, another low-fare airline, headquartered in Shanghai, China,  are both contemplating this method of increasing passenger capacity.

Airline passengers in the United States are unlikely to be allowed to fly with this “Standing Room Only” model since the US Federal Aviation Administration (FAA), the agency which regulates air travel in the country, stipulates that all air passengers above the age of 2 has to have a seat.

For  frequent fliers, it may give a different meaning to passengers flying “Stand By”.