[Avodah] First class and second class (economy) travel - in the Midbar

[SBA]

First occurrence of first and second class travel?

Baal Haturim, Devorim 1:31: dh 'Bechol Haderech asher Halachtem':

"...loshon rabim, shelo hoyo haderech lekulon beshoveh, eloh lechol 
echod ve'echod lefi mah shehoyo tzorich - hoyo ha'anan noseh oso - 
yesh bagovoha veyesh benomuch..." 
(source Sifri - which IIRC mentions 7 'classes')

SBA