Some countries that have issued ePassports with biometric information now have implemented automated kiosks at the airport so you don’t have to wait in line. For example, Australia has SmartGate, which gives eligible travelers the option to self-process through passport control. SmartGate uses the data in the ePassport and face recognition technology to perform the customs and immigration checks usually conducted by a Customs and Border Protection officer.
While in-flight on an airplane, most airlines (and all airlines in the United States) will not allow you to use your mobile phone. Some throughout Europe do allow their use; it is best to check with your airline. The reason many airlines do not allow the use of mobile phones in-flight is because they do not want the mobile phone signals to interfere with the plane's instruments and equipment. To stay connected, many airlines will let you use your mobile phone before the plane takes off and after it lands. Some also have onboard phones that you can use for a fee.
Information on epassports cannot be altered and epassports cannot be counterfeited, which was the primary motivation for putting chips in epassports. The information is protected by a cryptogram, or digital seal, in the chip. Any attempt to change the information would break the digital seal that was put in place by the Department of State and is unique to your data. Any tampering of that data would be immediately detected by the electronic passport reader and be evident to a border agent. Nor can the epassport be changed by border agents anywhere in the world.
The chip is just one of the many security features of the epassport. Though unlikely, if the chip fails your passport remains a valid travel document until its expiration date. You will continue to processed by the port-of-entry officer as if you had a passport without a chip.
More information is available in our epassport tutorial.
If your passport is expiring within six months: keep in mind that some countries will not admit visitors with passports expiring within six months or will not put visas them. So if, check with your destination and renew accordingly.
For U.S. passport questions, visit: http://travel.state.gov/passport/