The most common and most likely answer to this crossword clue is the 9 letter word MOTORCADE
I've seen this crossword clue in The Daily Telegraph
M
O
T
O
R
C
A
D
E
More clues leading to the result MOTORCADE
- Procession Democrat organised round Ohio’s capital
- Procession Democrat organised about first of October
- Against stopping revolutionary comrade’s vehicular procession
- String of cars transported Democrat round Ohio, principally
- Democrat shot around midpoint of “knoll” procession
- Forced to carry old metal band in procession of vehicles
- Procession with actor awkwardly getting in the way
- … street procession in way, steering car to opening
- Ohio Democrat stumbles in procession
- Worried actor taken in by fashion for fleet of cars
Buddy explains!

The straight part
We know that "fleet of cars" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fleet of cars = motorcade.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MOTORCADE mean?
MOTORCADE noun- A procession of cars carrying VIPs, especially political figures.
- To travel in a motorcade.