Many answers to common travel questions can be found by using the search box on the forum page. For example, for all the details about public transport between Milan and Bergamo Airport (BGY - official name Il Caravaggio Airport - also commonly known as Orio al Serio Airport after the location it is situated), including the exact location of the Stazione Centrale bus stops for these, please read this forum thread from just last year entitled "Bergamo" [ https://www.tripadvisor.com/ShowTopic-g18784… ].
You will find there that, in total, there are three competing bus companies that service the route between Milano Centrale Station and Bergamo Airport. If you wish to avoid Terravision, you can use the two others. As there are plenty of buses departing from virtually the same spot, no need to book anything online. Just grab whichever appears to be leaving next and pay your fare right there.
Thanks for the information. Great to know that Trip Advisor can help in so many ways.
Have a safe trip to Centrale...
I hope it will be ok. I guess some people are just unlucky. Thanks for your comment.
What have you read that is negative about them. Would be interesting to know. I've used the various buses more times than I can remember and never an issue.