Hey, Matthew: Is there any practical limit to how big passenger planes can get? They seem so huge now, I was just wondering if there’s some top size that they can get to before they just can’t fly. — Anonymous, San Diego

Yeah, the Airbus A380 can haul around a small town’s worth of folks at its maximum configuration. Of course, the size limit might have more to do with how long it would take to get all those people through inspections to get on the plane in the first place. Start shuffling through the X-ray machine on Wednesday for a Friday flight. But, actually, the state of physics being what it is today, there’s no limit to the size of a flying object, assuming you can generate enough engine thrust to haul the beast off the ground and to stay aloft. But, you have to keep in mind the fact that weight increases by a cube of the length, width, or height of your new Pterodactyl 5000. If you double the size of the A380, weight would increase by a factor of eight. Perhaps you can specialize in transporting very thin people with few clothes to keep things under control.

Photo by Rick Geary

What you need, obviously, is the strongest, lightest fuselage material you can find. The Airbus is 25 percent plastic. Comforting thought. It’s aluminum (like most other planes) reinforced by quartz, carbon, or glass fibers and plastic laminates. Take-off weight is calculated at about 650 tons and it cruises at about 560 miles per hour. It can take off on most runways that can accommodate a 747, so you don’t have to enlarge your airport into the next county. Boeing’s 787 is 80 percent plastic composite, but not as big as the Airbus. Each Airbus customer designs its own interior configuration, but the maximum passenger load is up to 800 fellow travelers in a double-decker style. So, theoretically, the only size limit to a plane is what the market can bear, and, boy, I’d say we can’t bear much more than we’re subjected to now.

Hi Matt: Why can foreigners like David Beckham, Yao Ming, and many others just pop over to the USA whenever they want, make millions here “working,” yet the foreigners who come to pick the lettuce get their butts deported as soon as they are found? If there is some easy way to get a work permit for the Beckhams, why can’t the poor foreigners get one, too? Sounds unfair to me. — CC, Vista

Part of your answer is the fact that nobody will pay huge sums for season floor seats to watch an anonymous immigrant pick lettuce. Beckham, Yao, and planeloads of athletes, performers, educators, tech specialists, biochemists, and other professional superstars can get past the migra easily with their O-1 visas. These are reserved for what the consular service calls “aliens of extraordinary ability.”

So, how do you prove you have extraordinary ability? You need some sort of “sustained national or international acclaim” and letters from peers stating what an extraordinary alien you really are. Cited often in the professional literature as an expert? Have a Nobel Prize or two? Film and TV personalities need to show some “advanced achievement.” Athletes need a “level of expertise not possessed by others” and must have risen to the top of their professions. Beckham seems to qualify, but there’s a lot of wiggle room in those descriptions. “Extraordinary ability,” in reality, might mean being over seven feet tall or being a handsome, photogenic British bloke.

O-1s must have a guarantee of employment before they enter the U.S. (Nike, in the case of Yao), and the future employer handles the visa-application process. Once you have your papers, the consular service considers you a “temporary worker,” not an “immigrant”; the visa says nothing about residency — just employment — and gives you no resident-alien status. If eventually you get booted off the movie set or out of the locker room or genetics lab, your employer is supposed to buy you a one-way ticket back to Shanghai or Manchester or wherever you came from.

The consular service offers 11 different kinds of temporary-worker visas covering different situations. If you’re a foreign employee of an extraordinary alien and your work is vital to keeping the alien extraordinary, then you get an O-2 visa. And in Beckham’s case, the adorable Skeletal Spice might get an O-3 visa identifying her as the spouse of an extraordinary alien, but that wouldn’t give her permission to work.