Originally Posted by
LondonElite
Since you are on two tickets, you are not protected in case of any IROPS. What this means is that if, for whatever reason, your DL flight to ATL is late or cancelled, or you do not check-in and show up for your BA flight on time, that entire BA ticket (including any return flights) will be cancelled. So, here are some things you should consider:
1. Leave lots of time between these flights (ideally overnight or 4+ hours). It is no guarantee, but it minimises the risk of the above going against you.
2. Your luggage almost certainly won't be through-checked on separate tickets, though there are occasional reports where it has been successful. You will have to collect your bags and then make your way over to the BA terminal where you will face security again (remembering to leave yourself time for this).
3. If you have already booked your flights, see if you can change the DL flight for more buffer.
BA can be quite unforgiving about no shows. Generally speaking, your BA ticket will lose any value it had if you no show and you may be required to purchase a new ticket at walk up prices.
Not only does DL have an interline baggage agreement with BA, but it has an interline ticketing agreement. You may purchase CHS-ATL-LHR on a single ticket. Typically from DL, but nothing prevents BA from issuing it. That will protect you should there be a delay on your inbound to ATL.
If you do choose to fly on separate tickets, leave yourself a lot of time to account for delays. The risks are all yours.