If you are a business traveler and spend a considerable amount of time flying around the country or globe, then consider carrying some traveler's survival gear in case you ever have to weather out life in a disaster-riddled city. Such a kit should be lightweight and contain: cash, passport, relevant maps, small first-aid kit, a few meal-replacement bars like Met-RX or Myoplex, flashlight, cellphone and charger, spare clothes, and water purification tablets.
While researching my book Surviving A Disaster, I spoke with many survivors and first-responders about what they recommended as the most important survival items on their list. The most common items that in all these cases were the ability to purify water and the means of maintaining personal hygiene. At the very least, carry Potable Aqua Iodine or Chlorine Dioxide tablets which will enable you to purify 25 liters of water per bottle of tablets. A Steripen is also good for purifying but you will want to carry extra batteries. For hygiene, stow some sanitary wipes or purchase a bottle of hand-sanitizer upon arriving at your destination.
Lastly, you may want to add an innocuous multi-tool like a Swiss-Tech 9-in-1 which lacks a blade but has many useful features. This gear can fit in a small fannypack but remember to check airline regulations, particularly with a multi-tool, as they are constantly changing.