This is obtained in S3L4. (Just after the "Indiana" achievement. See my other guide).
Just before the level is completed, you pop out into open air from being underground. On the left side and also pointing left there is a black boost spray, hit this as fast as you can which take you up a very long vertical jump. Once clear of the ground, transform into a bubble and go as high as possible. The achievement will pop when you are high enough.