Even if you're flying economy, it doesn't mean you can't access airport lounges. Most lounges sell day passes so that anyone can experience last-minute pampering and relaxation.
You can also get a Priority Pass ($99 to $399 a year), which gives you access to 850 airport lounges around the world.
Finally, check your credit card to see whether or not it gives you lounge access. Some, like American Express Platinum, have access to Delta and Centurion lounges.