(CNN) — Can you imagine flying on a plane with its own onboard gym, or popping into a disco mid-flight to stretch your legs?
While such travel concepts might seem frivolous nowadays, airline manufacturers were tripping over themselves to find innovative ways to utilize the space on new, larger aircraft when the jumbo era began in the early 1970s.
And some of the proposed designs were particularly out there.
Thankfully there's still photographic evidence of those that never made it off the ground, and the team at AirlineRatings.com have brought together vintage images of some of the most intriguing jumbo aircraft designs -- including an Austin Powers-style lounge.
"These new aircraft were double the size of the ones they replaced and thus there was space to be filled," explains Geoffrey Thomas, editor of AirlineRatings.com. "However they did not last long."
Dancing in the sky: McDonnell Douglas designed an onboard disco for its DC-10 aircraft.
Boeing Historical Archive
US aerospace manufacturing corporation McDonnell Douglas, now part of Boeing, was the brainchild behind the inflight disco experience design back in 1970.
Proposed shortly after the Boeing 747-100 jumbo jet took to the skies for the first time in 1969, changing the face of commercial air travel, it was devised to utilize the space on McDonnell Douglas' DC-10 aircraft -- as well as provide travelers with an unforgettable plane ride.
But the disco never came to fruition.
Undeterred, the ambitious manufacturer touted an inflight gym in the 1990s for its proposed "superjumbo" MD-12 , which would've been of a similar size to the Boeing 747, with a larger passenger capacity.
However the aircraft didn't receive any orders and the designs never took off.
"The jumbo disco was simply impractical, as was the gym because of turbulence," says Thomas. "The last thing you want is a drum kit or dumbbell flying through the cabin."
"Austin Powers Lounge"
Shagadelic: Mike Myers would be impressed with this lounge design.
Boeing Historical Archives
While McDonnell Douglas came up with some memorable failed ideas, they definitely weren't the only airline manufacturer dreaming up lavish jumbo passenger plane designs.
Boeing also devised some zany concepts, one of the standouts being a tiger-themed lounge for its 747, which at least got to the photo shoot stage.
Although the "Tiger Lounge" was shelved, the company persevered with its luxury lounge suggestions.
During the 70s, they attempted to introduce a downstairs lounge that wouldn't have looked out of place in Mike Myers' 1997 movie "Austin Powers: International Man of Mystery."
According to Thomas, it was the cost of weight and the certification which led to the underfloor lounge concepts being pulled.
"The lounge would also displace revenue-earning cargo," he adds.
However he points out that an underfloor lounge made it onboard the Pacific Southwest Airlines Lockheed Tristar "for a short time" in the early 1970s.
Boeing also tinkered with the idea of adding windows to the roof of its 747-81 service as well as sleeping cabins and a business class hub in a bid to boost the aircraft's appeal.
The designs were mocked up and advertised, but didn't get much further than that.
'Distorting the flying public's view'
This luxury onboard restaurant was also proposed for McDonnell Douglas' DC-10.
Boeing Historical Archives
A proposed onboard duty-free shop for the Airbus A380 suffered the same fate in the late 1990s.
The model was promoted heavily, much to the disdain of then Cathay Pacific Chairman Peter Sutch.
He apparently wrote to the corporation, asking them to stop advertising duty free shops, lounges and bars as he felt that any extra space on aircraft should be used for seats.
Thomas says he's not at all surprised that these particular designs never saw the light of day and feels they generated unrealistic expectations.
"Manufacturers have always striven to offer innovative ways to use the space on aircraft, particularly the hidden space such as under the floor and in the roof," he says. "However, these concepts distort the flying public's view of what is deliverable and at what cost."
While jumbo planes have had a lasting impact since they first appeared, the demand for large passenger planes has dwindled over the years.
So it's unlikely that travelers will be seeing onboard gyms and and discos on commercial flights any time soon.