Aliens have always had a weird place in My Traveller Universe (MTU). In Classic Traveller, most aliens are based on classic sic-fi tropes or stolen whole-cloth from other works. I listened to a recent episode of The Hydian Way (for FFG’s Edge of the Empire/Age of Rebellion RPG) where the topic was the cantina. They pointed out that in Star Wars (Episode 4 if you must) the cantina is really the only scene with aliens. The rest of the movie is very human-centric. Given I was playing Traveller at the same time as Star Wars, I think that subconsciously affected MTU. Surprisingly, this does not affect my boys who grew up with Ewoks and Jawas and Hutts and other Star Wars aliens who they see populating their Star Wars Universe as much as humans do.
As I have aged, I have come to see the dramatic value of aliens in MTU, and have occasionally tried to work them into my campaigns. With that thought in mind, I recently purchased Flynn’s Guide to Alien Creation for Mongoose Traveller. This short (34 page) pdf started with Universal World Profile and then uses directed 2d6 tables. In many ways, its not far off from the animal encounter builder in Classic Traveller. The result is a race that, though fairly well described, still have enough “unknown” that a referee can modify or embellish for a campaign.
Now, since the tables are random, the results one get may be a bit too random for some. In that case I can see using the table as a “directed builder” to capture all (or the most important) qualities to describe a new race.
Flynn’s Guide to Alien Creation is a good investment. The examples in the book can get a bit too repetitive (every step adds the one new quality while restating ALL the previous ones. As simple as it seems, this book is an invaluable addition to my Traveller library and will be getting much use preparing for the table.
Image courtesy RPGGeek
Rocky Mountain Navy Gamer 
Flynn’s Guide is a great little tool – I’ve used it for Classic Traveller as well and have been pleased with the results.