WiFi services aboard aircraft have become a necessity for many travelers and are available on more than fifty-five different airlines throughout the world. Many even allow telephone calls from your handset, as I wrote about on a Virgin Atlantic flight from Delhi to London. If you are a frequent flyer and need to connect with email and text messaging, Gogo in-flight Internet provides service throughout the continental United States on Delta, United, Alaska, American, US Airways, Air Canada, Virgin American, Japan Air Lines, Aero Mexico, British Airways, Aer Lingus, Iberia, Gol, Beiijing Capital, JTA, Hainan Airlines, and Vietnam Airlines. But it is expensive and the rates have been steadily rising. I realized on a recent flight that it was free to access their network on some airlines, thanks to T-Mobile and an offer I did not pay much attention to in the past.

In order to attract customers, T-Mobile introduced a clever promotion in June, 2016 that works on five of the Gogo-equipped airlines (Delta, American, Alaska, US Airways, and Virgin America) . It allows their customers to access the Internet and email for a free hour, and texts as well as iMessage, Google Hangouts, WhatsApp, and Vibe for the entire flight. For many years I have been paying Gogo for access even though they operate a relatively old system with limited bandwidth. In fact, American Airlines was a client that sued the company to break their contract because of poor performance, favoring ViaSat instead. Gogo immediately announced the system would be upgraded to better serve the flying public.

I am a customer of both Verizon and T-Mobile. I primarily utilize Verizon in the U.S. and T-Mobile in Europe because I believe they still have the best overall pricing in the industry for frequent overseas travelers. I had always believed that in order to log in for the free T-Mobile Gogo service I would have to do so with my T-Mobile handset (which I rarely carry or use here in the U.S.). That turns out not to be exactly correct. So I was curious as to how the Carrier insured that only the actual T-Mobile subscribers could access the service. I assumed that either T-Mobile or Gogo would verify the phone number against the SIM in the phone before authenticating the subscriber or the handset MAC address. This would insure that a valid T-Mobile customer was actually using the service with a T-Mobile handset.  That also turned out to be an assumption that was wrong. So how does the carrier assure the security of their service offering and protect Gogo in order to prevent just anyone, with any phone, from simply entering a valid number and getting a free hour of Internet and unlimited texts during a flight?

I contacted a senior representative of T-Mobile and also ran several tests with different Verizon and T-Mobile handsets (Google Pixel, iPhone 6S, and Blackberry Dtek60) while flying different routes in order to understand the limits of their free offering. T-Mobile assured me that they had certain validation checks in place to prevent what I just described but they admitted there were still some issues (as did Gogo when I spoke with them).

Here is what you need to know in order to take advantage of what I consider to be one of the most innovative offerings by a cellular carrier for their customers, especially business travelers:

• The service is only legally offered to T-Mobile customers on domestic and international flights with five of the airlines that contract with Gogo;
• Log-in requires you to enter your T-Mobile phone number. Once that is verified, you will be able to access the internet for one hour on that flight;
• T-Mobile told me that the offer was good on each flight segment that was flown during the same day. That turns out not to be true, as I found when I tried to access the network on a connecting flight. The system reported that I had already used up my one hour and that I would be able to purchase more time, but the free ride was over. Of course that was only part of the story if a subscriber had more than one phone number linked to the account;
• If you have a shared or family or business plan with multiple phone numbers, then when your time is up on one account, you can enter another phone number for another hour of service;
• The system is only available for smartphones and will not work with laptops or tablets;
• Text messaging will work on every flight without any time restrictions;
• If you pay an extra fifteen dollars per month for T-Mobile ONE Plus, and a five dollar surcharge for each line, then you have full flight Gogo access width no time limits throughout the Gogo system on the five listed airlines;

• While the normal T-Mobile plans allow an hour of free WiFi, the ONE Plus scheme provides unlimited domestic and international coverage on Delta Air Lines and the four other carriers. I almost exclusively fly Delta for overseas travel so this constitutes a significant saving. Gogo ordinarily charges an extra $35 for an overseas flight unless you subscribe to international service because only domestic coverage is include in their normal monthly or annual rate plans. Their plan that provides for full international service costs $80 per month;
• You can use any smartphone to access the T-Mobile promotion. The Carrier does not appear to be validating the phone number against the SIM, so this means that inputting a valid T-Mobile number will result in the ability to access the service. I spoke with a representative of Gogo Internet and they advised that this actually has caused some issues with multiple users attempting to utilize one phone number.
• You can use a phone that does not have a SIM card installed. I tested the system with an iPhone 6S with the SIM removed and it worked without a problem;
• If your account has several associated phone numbers, you can stack the access, one hour at a time. The system will allow each valid phone number equal access rights. It did not appear to matter that the numbers were all entered from one handset or different ones;
• You can use more than one number on the same account during a flight at the same time with different handsets. So if two people are traveling, they both have Internet access;
• You can use a smartphone with any SIM card for text messaging so long as you input your T-Mobile number for access. I sent and received text messages with my Verizon handset and SIM, using the Verizon Messenger Application. The messages were sent and received with my Verizon-assigned phone number and NOT my T-Mobile number. So I could continue to text with my Verizon account even though I was gaining free Internet access through T-Mobile;
• T-Mobile does not have a text messaging App like Verizon, but if you have a Verizon phone number, you can use it so long as you log into the network with your valid T-Mobile number;
• Whether the phone number is associated with a standard rate plans or the ONE Plus scheme, full text messaging is available on every flight;
• At the present time (until T-Mobile resolves the problems in their authentication system) a subscriber can, based upon my testing, use multiple numbers from one handset to obtain free WFi services;
• T-Mobile presently is only verifying that the phone number is valid, and then determines what type of in-flight benefits the customer will receive. My experience was that they were not cross-referencing the SIM against the actual T-Mobile handset, which would be the easiest way to deal with this issue.

If you fly frequently and want Internet connectivity in the air, then the economics of having a T-Mobile account can be very advantageous, especially considering their overseas rate structure that incorporates free text, email and Internet service throughout the world, and $.20 per minute phone calls. For the four phone numbers that I have with T-Mobile (for $120 per month plus tax) it will cost an added $20 per month, in total, to cover all four handsets in the ONE Plus rate promotion, including all taxes, as compared to my current Simple choice plan. Considering what it costs per-flight, or per-month for WiFi service, this is a real bargain, especially if your preferred air carrier is Delta Air Lines for international flights.