Zion
Hi Cheryl,
If I had to pick just one, I'd choose Zion. It's simply beautiful. The hike into the narrows is just striking and distinctive and something you'll always remember...particularly if you continue past the first place where you have to wade into the river. The sheer canyon walls rising up for hundreds of feet above you on all sides...the canyon so narrow that it's only the width of the river. The brilliance of the red rock walls...the outcroppings of green foliage...the lush oasis in the desert. It's a study in contrasts
The drive up through the tunnel and over to Mount Carmel Junction on the east side of the park is also not to be missed. When you come out of the tunnel on the east side, it looks like you're in a cartoon. You half expect to see Fred Flintstone come driving along any minute. Very distinctive and fun and different.
Bryce is nice, too...but I like Zion better. In addition, Zion is more accessible from the interstate than Bryce...and that is helpful if you have limited time.
As for an airport, both parks are closest to St. George...but that's a small airport with very limited flights. The closest major airport would be Las Vegas, NV.
Steve