As you have not mentioned anything about, what you have tried so far to solve this problem, I will assume that you have not tried anything and you have just deleted the mail from the Inbox.
Step 1: Using your web browser, go to AOL .com. In the top right corner of the AOL page, click on the envelope icon to go to AOL Mail.
Step 2: Sign in to your AOL account. When signed in, click on the Trash icon located at the left panel. This shall open the contents of your Trash folder.
Step 3: In the Trash folder, you will see all of your deleted emails that is not older than seven (7) days.
Step 4: If you want to recover or restore any of the emails in the list, click on the check box to select the email message.
Step 5: When the deleted emails are selected, click on the Action button above then in the pull down menu, click on "Inbox" under "Move To" group of commands. This action will move the deleted emails that you selected back to the Inbox.
Step 6: Congratulations! Your deleted emails must be restored to your Inbox.