Originally Posted by LoganFlyer

After discussing with 3Cforme, we've agreed that the post below, which I originally made as a separate thread, would be best done as a post here to keep all the discussion about bumping in one place. I've added a link to this post and a concise version in the Wiki for this thread in case people find it helpful.
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I've been lucky enough to get a whole bunch of bumps over the last 15 months amounting to $5800 in total compensation, and I've developed a strategy to maximize my chances. This is long, but hopefully these tips will help you out!

General tips:

1. BE PROACTIVE. I cannot emphasize this enough. If you just show up at the gate and wait for them to solicit volunteers, you will lose out on many bumping opportunities.
2. Be flexible in your schedule if possible. The next available flight to your destination might not be for several hours or even the next day. Luckily, I had a job where I had to show up at 8 AM on a given day, which meant I could fly to that city any time the day before. I would often take an early flight (think 6-7 AM) knowing that if I got bumped, I would still make it to my destination with time to spare. But if you have no flexibility in your schedule, you won’t be able to take the bumps.
3. The app is your best friend for figuring out if a flight is oversold within 24 hours of the flight. If you look at the standby list for your flight, it’ll show you how many seats are left and how many people have checked in but are waiting for a seat. Once there are more people looking for a seat than there are seats on the plane, it may be bump time! This isn’t perfect—some of those people may be non-revs who aren’t guaranteed a seat at all. But it certainly gives you a good clue. (In case you're not aware, to see this list, in your itinerary in the app, tap on "Upgrade/standby list." Then tap on "standby list.")
4. Don’t get frustrated by missed opportunities. There will be times you do everything right, but the gate agent doesn’t select you for the bump. For example, maybe they need to bump two people and even though you volunteered first, the next two people who volunteered were a couple and so the gate agent went with them instead of you. Gate agents can choose whomever they want to bump off a flight and sometimes it won’t be you. You can’t completely control the process and that’s OK. And of course, there will be those times you get a sweet offer, but then 10 people don’t check in or miss their connection and so they don’t need you. That’s also OK—don’t give up!
5. Always, always, always, always be polite to the gate agent! Remember I just said they can use any criteria they want when selecting whom they bump. You can be firm in your asking price while being polite—these are not mutually exclusive!

Now for the specific advice…

Step 1: Get on the bumping list during the check in process.

If a flight may be oversold, Delta will ask people as they check in on-line if they want to take a bump. This creates a list of people the gate agent can see at their podium. Some gate agents don’t use that list at all, but some do, so you want to be on that list. Here’s how to get on it:

1. Check in at delta.com, NOT the app. You can’t get on the bumping list through the app; you must check in through the Delta website.
   
   a. Key point here: if you’ve already checked in on the app, it’s not enough to go to delta.com, log in, and check in through the delta.com homepage. That just shows you your boarding pass; it doesn’t actually take you through the check in process again, and you’ll never get the chance to get on the bumping list. Instead, you need to drill in to your itinerary details and check in through that page. That will re-initiate the check in process and may give you the opportunity to get on the bumping list.
   
   b. Keep following the app! You may not get a chance to get on the list at exactly 24 hours out, but you may see later on that there are more people looking for seats than there are seats available. If that happens, go back to delta.com and check in again! Just make sure to keep point a) above in mind.
2. If you can’t get on the list by checking in a delta.com, you can still try to get on the list by checking in at a kiosk at the airport. Sometimes, a flight doesn’t become overbooked until much closer to the flight time, so the kiosk may allow you to get on the list while delta.com wouldn’t. I've even been known to go to a kiosk in the airside area to see if I could get on the list--this is especially effective if you're connecting. When you reach your connecting airport, if you're not on the list for the second flight, go to a kiosk in the connection airport and check in again.

Whether you get on the list by checking in at delta.com or a kiosk, it’ll ask you how much you would accept to take a different flight. The options shown will typically range from $200-$500, but you can type in any amount up to $800. I always put in $800. Only once (that I know of) have I had a gate agent use the list in order of cheapest bid to most expensive bid, but I’ve also had gate agents tell me there were giving me $800 because that’s what I bid.

Step 2: Talk to the gate agent early

Whether you get on the list or not, you want to talk to the gate agent in person as early as possible. They will know the exact status of how much the flight is oversold by. The gate agent should arrive at the gate 60 minutes before the flight for a domestic flight or 90 minutes for an international flight. I like to be at the gate 30 minutes before that, as sometimes gate agents arrive early. Some bumps are first come, first served, so as soon as they open up the gate, you want to be at the front of the line! Here’s how the conversation between me and the gate agent would typically go:

Gate agent (GA): “May I help you?”

Me: “Hi! I was wondering if this flight is oversold.”

GA: “Let me check.”

<types away furiously…>

GA Answer 1: “It is not.” If they say this, say thank you and move on.

GA Answer 2: “Yes, it is.”

Me: “May I volunteer to take a different flight?”

GA Answer 1: “I’ve got a list of people who are interested I’ll be choosing from.” In that case, I would ask them to confirm that I’m on the list. Or if somehow I couldn’t get on the list, I would ask them to put me on the list, but this had mixed success, which is why it's so important to get on the list while checking in.

GA Answer 2: “Yes, but I don’t know the details yet. What seat are you in? I’ll call you back up once I have backup flights.” If you get this answer, show them your seat, thank them, and then step away from the gate. They will call you back up.

GA Answer 3: “Yes, and here’s the backup flight and the amount of money I’m offering.” Negotiation time!

Step 3: Negotiations

If you get answer #3 , or you got answer #1 or 2 and they call you back up to the gate, then it becomes negotiation time! Every GA is different, but here are some general tips for negotiations:

1. Ask how much the flight is oversold by. This will give you a clue how much leverage you have. If it’s oversold by just 1, you’re probably going to get the gate agent’s first offer, since they can always find someone else. If they’re oversold by 10, you’re much more likely to be able to increase the price.
2. As a general rule, whatever they say, ask for $500 more. (An example conversation with a GA might look this. GA: “I’m offering $500 for this flight.” Me: “Can you offer $1000?”) You probably won’t get the extra $500, but it could get the gate agent to increase their offer by at least $100. And some GAs won’t budge at all. Worst they do is say no. They won't take you off the bumping list or think less of you because you asked for more money.
3. If you were confirmed in first class on the original flight, make sure to confirm you’ll be in first class on the backup flight. If you were in coach on the original flight, ask if they can confirm in you in first on the backup flight. Worst they do is say no. (See a pattern here? You don’t get what you don’t ask for!)
4. If it’s an overnight bump, make sure to explicitly ask about a hotel. Sometimes, they’ll assume you’re local and not offer one unless you ask.
5. Finally, if the flight is oversold by a lot, make sure to get the GA to confirm they’ll give you whatever they give the last person who agrees to take the bump. Sometimes, they need to up the offer to get more people to agree to the bump. They should give you and everybody that maximum amount they offered, but it doesn’t hurt to be explicit about it.

Special note here: say a flight is oversold by 14 and your minimum is $800 since the backup flight is the next day. They offer $400, and it seems no one is taking it. Should you wait for the offer to get to $800 before taking the bump?

Answer: absolutely not!! Get on the list at $400. Remember that last point about how everyone will get the same compensation whether they bid first or last. However, while the flight is oversold by 14, maybe they only actually need 10 people because 4 people don’t end up showing up. If that’s the case, the gate agent will go in the order people volunteered, so the people who volunteered last won’t get bumped and the people who volunteered when the offer was $400 will get the bump but still get the full amount offered at the very end.

Step 4: The waiting game

This can be the hardest part of all. Once you’re done with the negotiations, there is nothing more you can do except go back to your seat and cross your fingers. The days of Delta giving you the voucher immediately after the conversation above are long gone. Instead, you have to wait to see if everyone actually shows up. So don't go rearranging your plans in your destination city yet! Sometimes, they’ll know early in the boarding process they won’t need your seat and they’ll tell you to board. Sometimes, you won’t know until just before the door closes if they’ll need your seat. There’s literally nothing you can do except wait for the GA’s instructions. Pestering them while boarding is going on won’t help, so don’t do it. Just have patience.

Conclusion

There they are—most, if not all, of the tips I’ve learned in the last 15 months of getting bumped. Any feedback is welcome. Best of luck out there!