As long as two hours after the takeoff time, in the event that you show up later than expected, the carriers will give you another trip at no extra expense.
Assuming that you show up later than expected or after departure, you are as yet allowed to actually take a look at it for the flight 45 minutes before takeoff. Delta airlines booking then, at that point, plans the substitute flight.
Your failed to catch plane expense, if any, will rely upon the kind of ticket you have and how not long after departure you demand a rebooking.
Your gear will be quickly diverted by Delta Airlines when you actually look at it for the new excursion.