I'm curious to know if anyone else travels booking their tickets using their middle name?

Since I was a child, I always used my middle name. So my SM account is MIDDLE LAST. Changing a name on Delta is a huge pain and so I have, to this day, never changed it to FIRST MIDDLE LAST or FIRST M LAST. My credit cards are all issued to F. MIDDLE LAST.

I have Global Entry and PreCheck, and have flown all over western and eastern Europe and domestically with passport and driver's license and global entry all with FIRST MIDDLE LAST and tickets have always been issued in MIDDLE LAST. I've never been questioned by Delta, partner airlines, or TSA. I'm almost to 1M with no problems on Delta.

Is this a common thing and no one cares? Have I just not been questioned? Do I need to put the work in to fixing it now so I don't end up stranded at some point? I do have a few flights to the middle east coming up in the beginning of the year, so I am wondering if I should go through Delta and fix it.

Given that Delta is always a nightmare with their combinations of names, initials and prefixes, I'd love to just leave it.

My thought is that you have been lucky so far, others will disagree. I know at least two people who also use their middle names as a first name. Both eventually were advised to have that fixed. I also know people who's name is michael and their ticket said micheal and the TSA sent them back to the counter to have the name corrected. That is a bit over the top, in my opinion, but it did happen. Correcting your name with Delta
Sky Miles is not that difficult. It can't be done over the phone, but a quick fax to Delta with a letter of explaination and a copy of your passport or driver's license and it will be corrected almost immediately. If you do run into trouble, eventually, it will be a hassle. Your legal name is your legal name.

My thought is to fix your Skymiles account - you've been lucky so far with pre-check, but that may not continue. Your "Secure Flight Info" (where your KTN - Known Traveler Number is entered) is supposed to match EXACTLY to your GE info.

I'm surprised you get GE/Pre if your TT profile has first/middle/last but your bookings and SkyMiles profile uses middle/last. I do know that I signed up long long ago for SkyMiles using middle/last and when I tried to get it changed to first/middle/last it took several phone calls, runaround, multiple faxes, then I gave up because I booked as first/middle/last and that matched GE so I got Pre and MQM credit etc. and left it alone. Until, I flew on a partner and tried to credit to DL and they rejected it because the names didn't match So I tried one more pleading fax and that time it went through for some reason.

So if you decide to try to change it, good luck...

This is exactly why I have avoided it. That and I don't want to risk the GE/PreCheck known traveler stuff getting messed up and having to straighten that out. I'm sure I should do it - but I also almost always have a few tickets booked and then those names wouldn't match SM account - so there's that issue.

My middle name is on my passport. When buying tickets, sometimes I use it sometimes not. Some of my airline profiles have it, some not. I want to apply for GE. Do I HAVE TO use my middle name on the application, because it's on my passport? If so, will I always have to use middle name when buying tickets also? (And change my profiles if it's missing?) Thanks!

Delta changed the name on my account for the same reason very quickly. I just submitted scans of my passport and birth certificate. I got a confirmation email within a week.

Yes GE requires entering the name as on the passport. You can leave the middle name off the reservation, but need to have it entered as part of the Secure Flight Data field.

When my wife and I were being interviewed for GE, the person getting interviewed at the next desk (there were three interview desks in the same room) was getting grilled because she did no put her middle name on her application. Don't know the outcome as we got approved and were on our way before her interview ended.

That's the exact opposite of my experience during my GE interview. I asked if I had to spell out my middle name since I never used it and the agent didn't care either way. I ended up using only middle initial despite passport having it spelled out. Never have had an issue with it.