Why don't Continential Airlines planes have a letters in their tail numbers?

Question

For example, Delta's planes seem to always have numbers ending with DL or DA. United numbers end with UA. Continental planes seems to have only a number.

Answer 1

Tail numbers consist of a combination of up to 5 numbers and letters, either 1 to five numbers, or 1 to 2 letters.
Numbers begin at N1 and end at N99999. All N number with less than 3 digits can have 1 or 2 letters, except O and I. Numbers with 4 digits can have one letter only.
Mario, you can't have N166ER. It is on a 1954 North American T-28C that belongs to the Planes of Fame Museum in Chino, CA.
Delta and United use Vanity numbers like some people do on their cars, Continental just keeps the numbers assigned to the manufacturer when the aircraft is completed.

Answer 2

Many US registered airplanes don't have letters other the the N in the beginning. Private aircraft often have the owners initials at the end but I never could understand why somebody like Delta and United would bothered. N numbers can only be a foot tall and they spell United in eight foot tall letters all over the airplane anyway. So I can't see anybody checking the tail number to see if they can figure out who the sucker belongs to.

Several years ago, a freind of mine named Ken Engle owned a glider. His tail number was November one kilo echo. A well known shoe company paid him twenty five large to release the number when they bought their first jet.

Answer 3

Cause they can and they want to have only numbers...

An N-number is an aircraft registration number used in the United States. All aircraft registered there have a number starting with N. Due to the large numbers of aircraft registered in the United States an alpha-numeric system is used. N-numbers may only consist of 1 to 5 characters and must start with a number other than zero and can not end in more than two letters.

N10A to N99Z
N10AA to N99ZZ
N100 to N999
N100A to N999Z
N100AA to N999ZZ
N1000 to N9999
N1000A to N9999Z
N10000 to N99999


I want N166ER

EDIT:
John B I chuckled at your first paragraph... that's cool for Ken! Was it 25,000 or 25 million?