The Victorinox Swiss Army Knife can maybe be called the original portable gadget invented over 100 years ago.

Apparently the airline security regulations since 9/11 turned the Swiss Army Knife business up side down. From one day to the next sales fell by 40%. Victorinox bought the only other Swiss Army Knife company Wenger SA in April before it went bankrupt.
The Guardian has an interesting article with more details and interview with the Victorinox CEO.

Victorinox tries to adapt and introduced already a while a go the USB Swiss Army Knife. They also offer blade-less knifes to get around Airport Security. Still I am pretty sure even with such a model you will have a discussion with the security people at check-in.