Unless you haven't been on a plane in, oh, about 15 years, you've probably used an E-ticket as your document de rigueur. Even with the saturation there remains some confusion over what exactly an E-ticket is. 
An E-ticket is really nothing more than a reservation in an airline's computer system, one that advises them you have a ticketed seat confirmed on a particular flight.
When you're issued an E-ticket there's also a receipt that is printed out after. The E-ticket receipt looks similar to an old-style paper ticket but doesn't need to be presented at the check-in counter on the day of your flight. It only serves as proof that your ticket was issued.
To check in with an E-ticket you need only to provide a valid passport or government issued ID so the agent can pull up your record in their system. The check-in agent then provides your boarding pass to take to the gate. It is recommended however that you take the eticket receipts with you on your trip as it serves as proof of your reservation in the event of any major computer snafu or electronic glitch.
Traveling with E-tickets gives the added benefit of not
having to have valuable paper tickets with you along your travels, thereby circumventing the risk of theft, damage or loss.
Fun fact: Southwest Airlines is credited with offering the world's first e-ticket in 1994. A 2007 survey by IATA (the International Air Transport Association) said that 97% of all tickets worldwide are now issued as E-tickets. Environmentally speaking, IATA estimates that E-tickets save an equivalent of 50,000 trees per year by eliminating the need for the paper used to print them.
Airlines still do offer a paper ticket option but usually charge steep fees for them, upwards to $50 for the service.
E-ticket receipts can be a tricky thing to decipher given the amount of nonsensical travel-speak there. When AirTreks sends off your ticket email, included are instructions on how to read an standard eticket. For that Rosetta Stone, click here.
Paper tickets
There are airlines in the world, albeit not many, that still do issue paper tickets only for their flights. This is usually due to them using an outdated ticketing system and the value of them upgrading to the a more modern one for them is marginal.
Airlines still using paper-only ticketing systems are generally smaller operations and/or are low-cost local carriers. It certainly does not mean they're of low quality or at all unsafe.
If AirTreks needs to issue a paper ticket for any leg in your journey, we'll send you those tickets free of charge no matter where you are in the world. We’ll also make sure you know which legs of the trip have been issued that way and remind you that you'll need to bring the tickets with you to the airport.
* photo credits ReservasdeCoches.com and mescon