No,
it's 10:1, not 1:1. See here:
http://hhonors3.hilton.com/en/earn-u...ail/index.html
DELTA AIR LINES
Exchange 10,000 HHonors Points for 1,000 Delta miles.
The only hotel program that transfers 1:1 to (most) airlines is Starwood (SPG). But there you earn only 2 points per dollar on hotel stays with no status, while at Hilton (with point + more points) you earn 15 points per dollar on hotel stays.
Don't make assumptions based on comparing dining program earning ratios. The dining program earning ratios, while bigger "in print", are actually way worse for the hotel dining programs than the airline programs.
So if what you want is Delta miles, definitely
continue using the Delta dining program and forget about the Hilton HHonors dining program. (The only use for the Hilton HHonors dining program would be if you had no other way to keep your account active at least once a year. But since there are two credit cards for Hilton HHonors with no annual fee -- one from Amex and one from Citi -- the dining program for most people isn't even the best way of keeping Hilton HHonors points alive.)
Because of these transfer ratios, Hilton HHonors points are generally a poor value for converting to airline miles, and better used for hotels. The exception might be when you need just a
small number of miles to "top off" your airline account to get to an award level, and if you have no other (better) way to do that.