Here's Genesis 8:20-21 that deals with the events immediately after the end of the flood:
 Then Noah built an altar to the LORD and, taking some of all the clean animals and clean birds, he sacrificed burnt offerings on it.  The LORD smelled the pleasing aroma and said in his heart: "Never again will I curse the ground because of man, even though every inclination of his heart is evil from childhood. And never again will I destroy all living creatures, as I have done."
If God likes the smell of burning flesh so much, why don't Christians still have burnt offerings?
Surely the Bible endorses them.
So why aren't people still having them? (Don't count the Fourth of July barbeque as such an offering.)
I'm not going to hold my breath waiting for an answer. I've asked a number of other creationists the same question and never gotten an answer. It's just another question regarding their beliefs that they can't answer.