Would a metal sphere containing a vacuum float?

I too was wondering about the feasibility of vacuum for buoyancy, to help with flying cars. My intuition jumped to the presumption, posted above, that no material can surmount the pressure challenge. But two thoughts: 1) Isn't the real question, then, what the percentage gain (space saving?) from vacuum compared to helium, since helium is already feasible. 2) Compared to other technological miracles, wouldn't it seem that merely finding a material solution that can withstand a vacuum, would be rather pedestrian compared to for instance editing DNA? Maybe a bad example, but you get my point. I read the conclusion that even diamond wouldn't do it. But it the problem seems an odd one to have a status of "metaphysical illogicality," while granted, a vacuum is a special, spacial, spatial thing.

So I just did my own research and calculations, and given that a Boeing 747 weighs approximately 368 tons, the amount of pure-zero air displacement (as afforded by a vacuum) necessary to reach a weight of zero would be an astonishing 9.21 mil cu ft. The goal doesn't have to be zero, however, but rather just a significant reduction in weight overall. Still, given that total weight, it seems unlikely that any implementation of vacuum technology in commercial aircraft would be able to make a noticeable impact without a significant redesign, likely eschewing all currently-used materials, such as steel, in favor of much lighter materials. Perhaps we will be at a place in the future where carbon nanotubes or some yet undiscovered material is able to bridge the gap between thought experiment and reality with regard to the feasibility of such a technology.

The answers above reflect my own suspicion, but it makes me wonder if a large enough vessel, made of a light enough material, containing a vacuum within, would float in air. For instance, if you made a thin-walled rigid plastic sphere, weighing less than 0.08 lbs and of a volume greater than 1 cu ft, would it float away? As air weighs approximately 0.08 lbs/cu ft, logic would seem to dictate so, yet this seems like it shouldn't be possible. Is there some rule of physics which says that any known earth material constructed at the necessary dimensions to inhabit a large enough volume at a low enough mass to float in air would necessary be too fragile to support the vacuum within? If not, it seems like it would be useful to incorporate such devices into aircraft in order to reduce fuel costs. Imagine a passenger liner whose wings, tail, fuselage walls, and nose weigh less than air, such that the entire vessel's weight is reduced and therefor requires less energy (i.e. fuel) to achieve and maintain flight.