The reflex trash empty is the hard part, but AOL has one recovery mechanism past it worth trying quickly, since it operates on a short clock:

The straightforward case first, for anyone finding this before emptying trash: deleted AOL mail sits in the Trash folder for a retention period, recoverable by opening Trash, selecting the message and moving it back to the inbox or another folder. This is where most deleted mail lives until trash is emptied, the easy recovery the reflex empty skipped past.

Past the trash empty, AOL's restore feature: AOL Mail has offered a Restore deleted email function reaching back a short window, around 7 days on standard accounts, through the mail settings or a restore option in the trash area depending on the interface version. It attempts to recover mail deleted and purged within that window, not guaranteed but genuinely worth the two minutes given the alternative. The clock is short and running, so this is a today action rather than a this week one.

The honesty past the restore window: AOL, like most webmail, does not retain purged mail indefinitely and past the restore feature's reach the message is generally gone, with AOL support unable to conjure permanently purged mail back. The realistic remaining hopes are external, whether the message exists anywhere else, a reply containing it quoted, a copy in another account it was sent from or to or a client that had downloaded it before deletion.

The prevention the loss teaches: the reflex trash empty is the specific habit worth breaking, and for anything important, forwarding it to another account or a client that keeps local copies means no single deletion is final. AOL's own settings can also disable auto emptying of trash, keeping the safety net in place longer.