why pilots say roger?

Answer 1

It means "Message received"

It's actually part of a a code language used in 2-way.Radio communications

The "roger" is old USArmy/Navy phonix alphabet.

"R" is the code letter for RECEIVED,,like an abreviation.
"R" is Spoken over the Radio as ,,,pronounced,,,as "ROGER"

"received" is not real clear on a radio with cannon fire and engine noise in background.
but ROGER comes across very clear,,,for anyone's accent,speech/hearing.

When You HEAR "ROGER" it's clear the speaker said "R",,which means Received.

Used to hear "Roger Wilco"
Wilco is also a clear & distinct sound when broadcast.
It means "WILL COMPLY"

ROGER was obsolete long time ago,,,replaced by ROMEO

But ROGER is still "universally understood" because either Roger or Romeo still signify " R" which means RECEIVED.

hope that helps

Answer 2

From Straight Dope:

Pilots and other military types say “roger” to acknowledge receipt of a message or instructions. “Roger” at one time was the phonetic designation for the letter R, which in turn stood for “received.” Why not just say "received"? From a safety perspective, it makes sense to use standardized language, particularly when dealing with international operations. An American pilot may not understand German, but they both understand aviation terminology. The International Civil Aviation Organization oversees this standardization and disseminates it accordingly.
The use of “roger” isn't all that old. In the military's phonetic alphabet, "roger" didn't become the designation for R until 1927. (Previously the designation had been "rush.") The first citation given by the Oxford English Dictionary for “roger” in the sense of "received" dates from 1941, coinciding with U.S. entry into WWII. The term made the big time in 1943, when the Army Signal Corps incorporated it into one of its procedural manuals.
In 1957 "roger" was replaced by "romeo," the current designation, but by then "roger" = "received" was so entrenched that the brass knew better than to try and change it.
As for the use of “roger, roger” in Phantom Menace, the consensus seems to be that it's a sly (OK, not that sly) reference to Airplane (1980). The co-pilot in the latter movie, played by Lakers legend Kareem Abdul-Jabbar, was named Roger Murdock. This was the pretext for such lines as:
Captain Oveur (Peter Graves): Roger, Roger. What's our vector, Victor?
Variations on this theme include Oveur/over and clearance/Clarence. Trust me, it's pretty funny in the movie.

Answer 3

because the frist pilot was roger d muffin

Answer 4

hah! I just found this out a couple days ago! it is part of their alphabet enunciation system. "Roger" is the standard word for the letter "R". Why "R"? Because the "R" stands for "Recieved".

Answer 5

To let the tower know that they heard the transmission.

Answer 6

Because it sounds sooooooooo silly when they say "wilberforce" or "Thockmorton", or "Giles".