First Aid Kit: Go to the Thread "Which over-the-Counter med.s ....." This has been discussed in detail there. You can make a first aid kit on the cheap. Use a Pencil Pouch (6"x8") with one side clear plastic/vinyl. (Office Supply Store or Section about $2.75) This helps with security screenings and makes it easy to find the contents for yourself.
Carry your bulk medications and things in your suitcase. Keep your first aid kit in your purse, backpack, travel tote, etc. for easy access at all times. Just stock with what you need for the day. You can refill from your suitcase at the hotel.
Put your scissors in your luggage to be checked. You cannot carry blades of any kind on to the airplane. Plus, you won't need it on the plane.
Things to include - packet flushable wipes, small plastic zip-lock for waste, small travel size tissue, a few bandaids (not the whole package), any med.s you need - just enough for one day. (Keep rest in suitcase) Small 2 oz hand-sanitizer. A few sugar-free cough drops. Buy miniature (hockey puck shaped) pill bottles for med.s to alleviate bulk. Label them for yourself. (Wal-Mart and K-mart have travel sections with many of these things near their pharmacies.)