In these days of airline security paranoia, some strange things are banned from aircraft carry-on baggage. Some airlines allow crochet hooks, but some don't, and sometimes it depends on the mood of the airport security staff*.
I was invited to an online build day - a bunch of Instructablers got together via a Google Hangout, and this is my build - a quick and easy hack** to help Kitewife do crochet on the move. As well as being allowed on airlines, these shortened hooks are easier to handle in the confined space of economy class, or the passenger seat of a car.
*For example, American Airlines do not allow scissors longer than four inches, or "tools" longer than seven inches [link], which may be interpreted by some officials as "no crochet hooks"). Thanks to Sunshiine for reminding me about this point.
**Lifehack, modification and improvement of the product, all in one quick Make!