In the early 90s, there was a popular song that played on the radio a lot, and was mostly just one person whistling for the entire song. I can’t remember the name or band, so thought I’d turn to you all for help. I’ve always been impressed by the talent it takes to whistle a tune…my range of notes is abysmal.
Not sure if this is what you’re thinking of, but “Patience” by Guns-N-Roses begins with a long whistling solo.
Also, “Winds of Change” by the Scorpions has a whistling intro.
Also, there’s a lot of whistling in “Don’t Worry, Be Happy”.
Billy Joel’s “The Stranger” begins and ends with whistling.
This one I know:
Artist: Newton.
Track: Streamline.
But I think the whistling is not produced by a human mouth; it’s surely a synth.
My vote’s with Bobby McFerrin’s Don’t Worry, Be Happy
For a while, you couldn’t pass a radio without hearing it.
Roger Whittiker is known for his whistling, but I’m pretty postive he did not have a popular song in the 90’s that you heard on the radio all the time, unless it was a surreal remix by someone happening. Although, now that I think about it that might be pretty cool.
Doogie Degli Armonium had a very popular tune called “Wanted”, but that was in the late 70’s. It was all whistling, too.
I’m not sure if MaceMan was questioning about an all-whistled track, often hard to identify; because it somehow harder not being able to know the name of “Don’t worry, be happy”.
I wish MaceMan would tell us if he’s figured it out. It’s starting to bug me now. 
Thanks to all who’ve replied. I think Tangent’s suggestion, Scorpion’s “Wind of Change,” might be what I was thinking of, although I thought there was a lot more whistling than that! However, the whistling parts definitely match the tone and feel of what I remember, and I know it was done by a rock or alternative rock band–so I’ll have to conclude this was it!