Also, people always say that the US is the only country that uses feet, pounds, miles, etc. But there are a lot of other countries that still use those units, or at least understand them, even if it's not an official unit. I even work with engineers from China who use and understand Imperial units. I also visited a friend in Ireland who had a (pre-digital) scale that measured weight in stones.
- Light aircraft use nautical units.
- Ultralight use metric for speed and distance but feet for altitude and vertical speed
- Gliders use metric
- Charts use feet for altitude. Aviation authorities define airspace using nautical units but ground authorities use metric for things like fly over altitudes. All converted to feet in charts but the legal text use meters.
- AFAIK, mechanical parts for non-US built aircraft are metric. Pipe fittings have always been in inches for some reason, but commonly converted to metric (1/4in is written as 6.35mm).
- Mostly US paper sizes
- Pounds for human weight
- Ounces and pounds for weight,cheese and meat cuts in the supermarket.
- But metric for pre packaged products(they usually come in sizes similar to imperial though, like 450 grams)
- Gallons for gas and large sized bottled water
- But liters and millilitres for small bottles of water...
- And quarts for motor oil.
- Liters for duty free alcohol and spirits,but "bottles" for locally sold alcohol.
- US units for clothing and shoes
- But yards for fabrics/textiles
- Metric units for construction areas
- Colonial units for land areas and agricultute