TrueCrypt accomplishes the same thing of encrypting and hiding your data. There is no need to use a second application. If you think about it, there isn't sufficient need to hide the data on your flash drive. Feel free, but it is over kill in my opinion.
And if you really do need to “hide your data”,
TrueCrypt provides methods of
plausible deniability, including naming the encrypted file whatever you please and the use of a
hidden volume inside another encrypted volume.