It's very good. Maybe try to put your slogan on there somewhere. Perhaps also extend the blue colour on the tail down onto the fuselage at the back a bit - there isn't much on the back of the plane. Something like the Skywest or Afrikaans ones above.
Regarding uploading the logo, resize it to 300 pixels wide, 90 pixels high (or less), and under 500 kb. It must also be in jpg, png or gif format. Then click on Admin (on the top line of the menu bar) and go down to the Airline Logo section. Click Choose File, browse for it, then click Upload. You might want to move your slogan on the logo to the side so you can have everything larger - as the AM logos are quite wide, not square.
The logo will only be uploaded for the one world, you will have to repeat the procedure for each separate world.