What if you found yourself stuck alone at a faraway airport -- with no money, credit cards or ID? How easily could you fly back home again?

You might survive if you had a smartphone. Emerging "empty pockets" technology is increasingly allowing travelers to use their phones to make purchases, book flights, check in and board planes.

Wallets? They're so 2008.

Delta, American and United are already big into electronic boarding passes on smartphones, and stragglers like JetBlue are planning e-boarding programs in the near future.

What's next? If some visionaries have their way, the future of mobile travel will touch virtually every key activity at the airport -- including security and U.S. passports. Smartphone technology might improve airport efficiency and help ease the pain from skyrocketing traffic predicted in the next 20 years.

But is a post-9/11 world comfortable with the idea of merging personal cell phones into the airport security network?

Apple -- still basking in the afterglow of last week's iPhone 5 curtain raiser -- is also unveiling Passbook, an app which organizes e-boarding passes, flight reservations, coupons and other documents.

But Apple has a much more grandiose plan for its empty pocket dreams, according to public U.S. Patent and Trademark Office documents. Read the patent document (PDF).

For example, imagine checking bags with your cell phone -- or passing through security by flashing an official driver's license or U.S. passport displayed on your phone.

Outside the airport, envision using just your phone to rent a car or to check into a hotel. How about using your phone as an electronic hotel room key?

But let's get real, say industry experts and government officials. As cool as all these ideas sound, extending Apple's technology and influence to airport baggage tracking and TSA security would be unprecedented.

"I'm always kind of staggered by the scale and complexity and the ambition that they have," says mobile phone industry analyst Nick Holland of Yankee Group.

As you might expect from the secretive folks at Apple, they wouldn't talk to CNN about the patent documents. But we did grab some time with "Apple Insider" reporter Neil Hughes, who covers nothing but Apple, including its patents for future products.

"Security may be the biggest issue," says Hughes. Carrying all your personal ID and travel documents on a single device would be very tempting for skilled password hacks, says Hughes.

The concept

The 2008 patent application was approved in July and filed under the working title "iTravel." Hughes suspects the iTravel concept will be folded into Apple's Passbook app, which will be available for download on Wednesday. Right now, Passbook will store electronic versions of airline boarding passes which will automatically pop up on iPhone screens when you arrive at the airport. The phone knows where you are, thanks to geo-locator technology.

That aspect alone will make a lot of gadget-geeky travelers feel all gee-whizzy inside.

Even more gee-whizzy: The patent calls for iPhones to automatically check in luggage when passengers approach an airport baggage check-in kiosk. (See details in the photo gallery above.)

Would security benefit from smart-phone based e-passports and e-drivers licenses? Would they increase speed, efficiency or security at TSA check points?

Currently -- as most of us know -- TSA agents briefly examine government ID and boarding passes as each passenger presents their documents at a checkpoint at the end of a security line.

Under Apple's patent, a traveler's phone would automatically send electronic identification to a TSA agent as soon as the traveler gets in line.

While each traveler waits in line, TSA agents would examine the electronic ID at an electronic viewing station.

Next, at the X-ray stations, a traveler's phone would confirm to security agents that the traveler's ID had already been checked. Throughout the process, the phone photo could be displayed on a screen for comparison with the traveler. Facial recognition software could be included in the process. (See details on Apple's proposal in the photo gallery above.)

The patent documents offer a surprising number of details which open doors to key questions about the system, but Apple declined to discuss the patent.

The TSA wouldn't comment either on the viability of Apple's plan. But other government officials, aviation authorities and longtime industry experts say Apple faces at least three high hurdles if they want to see this idea to fruition.