The ball was in play the winger kicked the ball for the side line, the ball went outside of the line in the air, the wind blew it back into the playing field, the other teams winger caught it but the ref over ruled the linesman and gave a line out. The ball never touched the ground outside the line.
If the situation is exactly as you describe, then it would appear that the referee may have made a mistake.
This is covered in Law 19 definitions, where it lists when a ball is, or isn't in touch. As you can see below, if the ball crosses the plane of touch but doesn't touch anyone or anything, then it's not in touch. If the ball then comes back into the field of play (blown by the wind, but still in the air)....we play on.
Law 19 Touch and Lineout
TOUCH - DEFINITIONS
The ball is in touch when it is not being carried by a player and it touches the touchline or anything or anyone on or beyond the touchline.
Your example did not fulfil the above description, so it is not in touch.
Thanks for the question
The Rugby Ref