Kayak
Display of a valid state registration decal
In addition to registration number the display of a valid state registration decal.
Display of a valid state registration decal
Display of a valid state registration decal
Display of a valid state registration decal
a sailboat
both sides of the bow
The student number is needed to register for the course.
Canoe
Six
Military aircaft display national markings in order to be identified by other aircraft as enemy or friendly. Modern US Air Force jets use markings that lack color and are shades of the camoflage. Civilian aircraft are only required to carry a Registration identification number. This registration ID includes Letters and Numbers and each country has a unique prefix Letter(s). For example, all aircraft registered within USA begin with "N" and this registration is commonly referred to as the "N-number". However, I do not think a civilian aircraft is required to display the national flag.
Vehicle registration numbers are a means of determining the owner of a vehicle. Usually, when purchasing a vehicle from a dealer, the dealer will transfer the registration number to the purchaser and fill out the required forms.