I’ve pretty much set up everything to be paid by my Delta American Express card now except for my gas bill. They are still living in the 1900s and make you pay by check.
Today I happened to be on their website and noticed that for a $1.99 fee, you can pay by credit card. They don’t American Express, but do take Visa and Mastercard. To avoid the fee the next couple of months, I went ahead and initiated a payment of $300 so I’ll have a credit on my account towards future bills.
You may want to check out your own utility and gas company to see if they offer credit card payments as well. Whatever it takes to get miles!