What technological advancement allows passengers to bypass physical tickets when traveling on airlines?

The correct answer encompasses all the listed advancements, as each plays a role in allowing passengers to bypass physical tickets when traveling on airlines. Smartphone boarding passes represent a significant technological shift; they enable travelers to receive their boarding pass directly on their mobile devices, eliminating the need for a physical printout. This convenience not only saves time at the airport but also enhances the travel experience by reducing the likelihood of losing a paper ticket.

Internet reservations contribute by allowing travelers to book flights online and access their tickets digitally. This streamlining of the booking process means that passengers can manage their travel plans more efficiently without needing to deal with physical documents unless they choose to print them.

Two-dimensional bar codes, often used in conjunction with smartphone boarding passes, facilitate quick and easy scanning at checkpoints. These bar codes store essential flight information and can be scanned from a mobile device, again negating the need for a hard copy of the ticket.

Together, these advancements illustrate the broader trend in air travel toward digital and mobile solutions, enhancing the efficiency and convenience for passengers. Thus, recognizing that each technological aspect is integral to the ability to bypass physical tickets justifies selecting the option that includes all advancements mentioned.