How long should a package sent international airmail from uk to us take?

7 - 10 days. Depends on from where to where. within these countries. Also depends on whether there's somehting in it that may require customs attention in which case it may be weeks. If customs decide they're going to charge duty or VAT on it there'll be an £8 clearance fee +duty+VAT on the value of the whole sum of value of goods, postage charage and duty. To cap it all, the Parcelforce system for collecting duty by credit card over the phone has broken down and has been broken for a long time. They collect the clearance fee +VAT+duty from your credit card, but becuase the system is broken it doesn't release the goods. They wait until the customer complains and THEN take action. If it comes by Royal Mail Letters instead of Parcelforce you've got to go into a specified sorting office (20 mile round tirp for some of us) and pay the money in person within so many hours or they dispose of the package.