Hi folks
I work in the airfreight industry and can say hand on heart that you have nothing to worry about. The UK leads the world with air cargo security. We have had the strongest measures in place have done since just after Lockerbie.
As 90% of all air cargo moves on passenger aircraft (apart from small parcels via DHL/UPS/Fedex who use their own aircraft), all cargo is screened before it goes anywhere near the aircraft. There are various different ways of doing this, which I can't go into on-line, but trust me its a pain the **** when the customer is screaming at us to get their freight out and away, but one thing that is never shortcut. US customs also have to pre-authorise every piece of cargo with a destination to or via a US airport or port
BEFORE it leaves origin.
The USA now has a "100% screening" of all air cargo that boards aircraft in from US airports and has further increased security following 9/11 and has actually copied the UK regulations.
If this weekend has highlighted anything it has shown that the security measures in place worked.
As someone has said before, don't let the muppets win and stop you, thats what they want.
Keep calm and carry on, thats what Britain does!!