Ok first off my husband is a commercial plumber and only deals with installing new stuff but this is stumping him as he has tried several things when he has had the time to mess with it.

Several weeks ago we noticed that our hot water lines... mainly in the kitchen and one bathroom faucets have terrible air in the lines. Not too noticeable in the washer, downstairs wash tub, showers and other faucet. Also our hot water lines have lost pressure. Extremely noticeable in the washing machine, which I am assuming would be the closest to the hot water heater. And our hot water doesn't seem to be as hot or staying as hot as it always has.

He has checked the hot water heater, changed out a part of the pipes that he said was clogged a bit with hard water, we had the town come out and flush the lines since we are at the end of the line. The town says we have no leaks outside. My husband says the elements in the heater aren't going bad. He is at his wits end with it. He says the only other thing he know is try getting a new hot water heater but since he doesn't work in residential plumbing I thought I would ask on here and see if I could get some suggestions before doing so.
Thanks so much!!

Tell him his dip tube is failing. Do a search on dip tubes. As for the air, I would need more info.

Thank you SO much! I will pass that information on to him. After reading a bit on them I believe that sounds like it might just be the problem. Him being a plumber and he has asked around to several guys that work for his company no one has mentioned the dip tube. Hopefully this will solve the issue. We will work on that and then work on the air issue. Thanks again!!

After talking with some others and asking about the dip tube they decided that was the problem so we replaced the hot water heater. That also solved out air problem. Thanks so much again!

If you don't keep it dust free around the bottom of the heater, assuming it is gas, you will be asking us why you have no hot water in about 3 years.