I live in a bad neighborhood and, thus, carry a knife for self defense.

When I fly, I never check any baggage (not worth the hassle). I don't take my knife with me when I'm flying because I don't know what I can do with it. However, I've recently starting flying several times a month and I'm starting to feel like my personal safety is being threatened by my inability to take my knife.

What can I do? Do any airports have lockers or something similar?

Never take a knife to a gunfight.

Seriously, though - there aren't any lockers anymore (TSA is deathly afraid of lockers). Why not just buy a new knife each time you travel once you reach your destination?

Sadly, most airports no longer have lockers because of the filthy litttle cowards at the TSA who have prohibited their use.

Can you leave your knife in your car?

This is not a helpful suggestion to your question but ...
1) is that legal where you live?

2) if you were concerned enough that you wanted to carry a weapon (and it was legal, depending on how you think about these things), wouldn't it make more sense to carry CS gas or something that didn't require you to be quite so close to your hypothetical attacker?

If you can't be bothered to discuss this because it's not on-topic, that's fine.

Actually, I was surprised to see there is a bank of lockers in Concourse E at PDX.

You're joking right? Besides, airports usually don't have knife shops.

I don't have a car. I take public transit and walk the streets of Baltimore, which is why I need a knife.

1) To tell you the truth, I don't know.
2) I don't actually plan on using it. It's more a deterrent, so that if someone comes at me I can make them hesitate, buying myself some time to run. I don't think a little spray bottle would make an attacker think twice.

Well lockers are not prohibited by TSA -- it is just that they have new rules for them. MSP has a ton of lockers airside. I use them quite frequently when I have to make a same day connection between two different ittns. Just go out to the car and switch bags/repack, and then off back through security. I put the computer bag in the locker, and don't have to deal with that nonsense on the way back through.

TSA only required the use of a biometric (at MSP a fingerprint scanner) when using the locker. No actual personal information about yourself is obtained. So they have a fingerprint, but nothing else. What I think is that most airports were not willing to invest in the technology to keep the lockers open to the traveling public.

Do they work?

"Only"?

I think that's a very unreasonable request, both from a privacy standpoint and from a cost standpoint.

If you aren't willing to use it, don't carry it. If someone is attacking you, they will see the hesitiation in your eyes..

A spray bottle full of mace or pepper spray will deter most attackers.. especially if you have to spray it at them. It has a range of afew feet. Your knife has the range of your arms length.

In Baltimore/DC area, you have heavy weapons restrictions. http://www.packing.org is a good reference site. Its mainly about guns, but they also list knife/mace/other non-lethal weapon laws for each state, along with links to where the information was found.

If you don't know how or where to store your knife then you probably should not be carrying one for self defense. It will probably be taken away and used against you. Maybe this would help http://members.aol.com/ThaiRing/street.html

Just because I don't want to cut anyone, that doesn't mean I'm not willing to use it. I'm quite ready to waive it in a menacing fashion and yell "I'll cut you foo!". Anyway, I try not to let anyone on the street get within a few feet, and beyond a few feet I feel that a knife is a better deterent than a bottle of mace.

Your suggestions are really off topic though since the TSA does not assigned fewer restrictions to Mace than knives anyway. Furthermore, there is the more general problem about what to do with essential, but prohibited items that cannot be cheaply replaced.

When this was still a free country, I knew how and where to store my knife. The fact that US citizens can no longer travel without submitting to search and seizure is completely unrelated to my competence in carrying a knife.

You make it seem like your attachment to the knife is very strong. However, it's obviously not as strong as the desire to avoid the "hassle" of checking bags. My suggestion is that if the knife is that important to you, you should be willing to put up with a bit more hassle at the carousel. That is, check it with your bag. If you're not willing to check the bag, the knife must not be so important.

My only other thought is to find a concessionnaire at or near the airport (car park, motel, diner ...) willing to hold your knife. Perhaps if you always have a meal at a diner near the airport on your way out (and leave a nice tip) they'd be willing to hold the knife for you.

I've got a better idea for chunk.
Ditch the knife and move to a city and/or neighborhood where you won't feel the need to carry a knife everywhere you go.
I've lived in Chicago twice, Baltimore, Boston, Detroit and currently in the LA area and have never once felt the need to carry a weapon. Plus I've traveled to many of the world's tough spots...Bangkok, Hong Kong, Moscow and Newark, NJ ...and have avoided trouble by not cruising the mean streets.
You need to get somewhere safe and sane as soon as you can arrange it.

thats my second recommendation. I've lived in bad areas myself. I've had guns drawn on me. Thats why I moved out into the country a bit. Yes, I have a 45 min commute to work, but for the extra safety I feel at night, its worth it to me