L' and le - both of which mean "the" in English -- are the articles which are used with the French word avion. The choice depends upon whether the article directly comes before the masculine singular noun - in the first case - or has an intervening word - such as an adjective or number, in the second instance. The pronunciation will be "a-vyo" in French.
Par avion. (by airplane, used on airmail)
avion
Avion.
animal, avion, automobile
'un avion' is a plane. Avion is not a Spanish word, but a (recent) French word modelled after the Latin 'avis' meaning bird.
plane un avion
an airplane is called 'un avion' in French. The old word 'aéroplane' isn't used any more.
In French, "sofa" is a masculine word. The article "le" is used before sofa.
The word that is used in Modern Foreign Languages (MFL) now'a days is Un Avion which is masculin.
The french word "la" is a feminine word, in fact, it is the state of all the feminine words in french.
The Spanish word, avion, is Bird in English.
In French, the word "voyage" is masculine. It is used with the article "le," so you would say "le voyage."