Clapton is small. You'd be lucky to fit one lens, assuming it doesn't have a lot of zoom. If you have a compact dslr, I think clapton would still be too small. Clapton also has thin straps and not a lot of reinforcement where the straps connect to the backpack. If your camera and lenses are too heavy, you may cause excessive wear to happen too quickly, which can lead to breaking.
Neonoe would easily be your best bet for a dslr. However, neonoe can hurt the shoulders when the bag is heavy (thin straps). The bag's bottom also sags with heavy weight. The divider also doesn't go all the way to the bottom, so be prepared to dig through the bag. That can get annoying real quick if there's a dslr in there that you have to be mindful of. Neonoe is my absolute favorite bag, but I would never put my dslr and lenses in it.
Neonoe isn't going to offer your camera any kind of protection, like if you accidentally knocked it into something. Neonoe is bulky, so it can happen. If you have a protective slip, like Ape Case, it can fit but it will be very snug. You would only be able to use the slip for a dslr body and one lens, with little to no zoom, only. If you have more gear + protection the entire neonoe would function more as a camera bag, and nothing else.
For intl flights, I like to use artsy. I am able to bring two lenses, including a telephoto, the camera body, and their respective protective slips in artsy. I have ample room to carry my wallet and various pouches. It technically works, but after one day of doing that, I decided to just use my regular camera bag. My gear means a lot to me, so my attitude towards protection may be a little more than most people's. I'm involved in the creative fields, and a good camera is necessary for me. I would much rather have an ugly gray lump at my side that protects my things well.
As for neonoe and safety, I haven't had problems using it on public transportation. I also use my neonoe for domestic flights. I do my best to be aware of my surroundings. If I'm somewhere crowded and people have to get close, like on the subway, I make sure that the open tops of my bags are in front of me, and are in my line of vision. Most of my bags have no kind of closure, and I treat them all the same way. I travel most often to SE Asia, and the same rules apply. Just be aware of your surroundings and keep your things in your sight.
Backpacks are actually one of the worst things to travel with btw, since people can easily open them without your knowledge. They also make easier targets for slitting with a knife and emptying contents into a different bag.
Long story short, if you want a good all-purpose handbag, neonoe. If you want something for bare essentials, clapton. If you want something for your camera, stick to an ugly, but protective, camera bag.
