KSH CAT Two files into one

Quick question,

File A has one line (10 charachters), File B has one line (10 charachters).

how do a concat these two files together to produce a file (File C) that has the contents of Files A + B together onto one line of 20 Charachters

if I use:
cat FileA FileB > FileC

I get the following in FileC:
AAAAAAAAAA
BBBBBBBBBBB

When I need it on one line, i.e.
AAAAAAAAAABBBBBBBBBBB

Thanks.

cat fileA fileB | tr -d "\n" >fileC

cat fileA fileB | sed 'N; s/\n//' >fileC

awk -v ORS='' '{print}' fileA fileB >fileC

paste a b | sed 's/\t//g'

Strange !

This ORS - Output Record seperator is not working for me