I have a question what does the last two letters on tail number indicates?
Sometimes something sometimes nothing. you have a specific example?
I am at the Delta terminal at LGA. Some delta has DL some with JQ. JQ seems to be operated by Shuttle America. So do they i dicate who bought the plain?
Yup. RW, MD and MA from the MidAtlantic days and RQ currently and UW on birds transfered from US.
The registrant can choose any two letters that they want that aren’t currently taken (and aren’t an O or I)
From the Wikipedia article on aircraft registration:
In the United States, the registration number is commonly referred to as an “N” number, because all aircraft registered there have a number starting with the letter N. An alphanumeric system is used because of the large numbers of aircraft registered in the United States. An N-number may only consist of one to five characters, must start with a digit other than zero, and cannot end in a run of more than two letters. In addition, N-numbers may not contain the letters I or O, due to their similarities with the numerals 1 and 0.
Each alphabetic character in the suffix can have one of 24 discrete values, while each numeric digit can be one of 10, except the first, which can take on only nine values. This yields a total of 915,399 possible registration numbers in the namespace, though certain combinations are reserved either for government use or for other special purposes. With so many possible calls, radio shortcuts are used. Normally when flying entirely within the United States, an aircraft would not identify itself starting with “N”, since that is assumed. Also, after initial contact is made with an aircraft control site, only the last two or three characters are typically used.
The following are the combinations that could be used:
N1 to N9 — Federal Aviation Administration (FAA) internal use only N1A to N9Z N1AA to N9ZZ N10 to N99 — Federal Aviation Administration (FAA) internal use only N10A to N99Z N10AA to N99ZZ N100 to N999 N100A to N999Z N100AA to N999ZZ N1000 to N9999 N1000A to N9999Z N10000 to N99999
An older aircraft (registered before 31 December 1948) may have a second letter in its identifier, identifying the category of aircraft. This additional letter is not actually part of the aircraft identification (e.g. NC12345 is the same registration as N12345). Aircraft category letters have not been included on any registration numbers issued since 1 January 1949, but they still appear on antique aircraft for authenticity purposes. The categories were:
C = airline, commercial and private G = glider L = limited R = restricted (such as cropdusters and racing aircraft) S = state X = experimental
For example, N-X-211, the Ryan NYP aircraft flown by Charles Lindbergh as the Spirit of St. Louis, was registered in the experimental category.
As mentioned elsewhere in this thread, the letters may or may not mean anything.
Any legal combination of numbers and letters can be requested. Often airlines will try to get the letters to match their airline code (e.g. AA). (Continental prior to its merger with United was an exception. Its aircraft had 5 numbers and no letters. They were quite often consecutive numbers.) A private aircraft’s owner may wish to have his aircraft registered with his initials in it (e.g. N69DR).
When fleets were small, it was cool to have all your planes end in DL or EA or UA,
but now that is just not possible with so many planes out there…