With H3O+ there is no reaction other than exchangeable protonation of ethanol molecules. CH3CH2OH + H+ <===> CH3CH2OH2+.
Reactions giving dehydration and ether formation require concentrated H2SO4.
alcohol + acid —> alkene + H2O (water)
Note: H3O+ is the strongest acid which can exist in water:
ethanol (CH3CH2OH) + [H3O+] —> Ethene (CH2=CH2) + H2O
It follows an acid catalyzed dehydration of alcohol mechanism.
However, there is another product that you could get:
CH3CH2OH + [H3O+] —-> CH3CH2-O-CH2-CH3 (diethyl ether) + H2O
However, whichever product you get depends on the temperature conditions, and I think the strength of the acids involved, but mostly the temperature conditions.