Dude..... The terms they use "...to get you going." is clear as crystal. To go and use the training arena, you will need to start your trial. If your trial is finished, you will need to sign up for a month (hence the credit card)
What you should do, and all new people do, is don't start the trial, go to the offline arena and fly a few weeks. get used to the game by yourself and learn how to fly. Then start your trial so you arent wasting a week just figuring out how to lower your flaps!
I still don't understand why I have to give my credit card details at this point, to use the training, so I can actually play the game, even if it is free for two weeks...
And although my 2 weeks was over 20 months ago, at that time, TA was available during the trial.