Ainsworth was delighted to put pen to paper on a two-year deal at Loftus Road, but thanked the Cardiff fans for their "awesome" support.
"Cardiff fans are the best supporters I have ever played in front of, without shadow of a doubt, and it will be hard to top them," said the 30-year-old winger.
"I wish I could take them with me because the support they gave me was phenomenal. It brought a lump to my throat.
"Very few clubs could hope to match them, but I think QPR could be one of those.
"I turned down three First Division teams to come here because of the ambition at the club.
"They are a lot like Cardiff in that they don't just want promotion, they want to go all the way to the top.
Full story.