Hello I need to copy all kind of files into a folder, but I want to copy the files into internals folders.Example

I have a folder whith this:
a.txt, b.txt and the folder "newfolder".

but "newfolder" has:
c.txt and d.txt

I want to copy (whith a MS-DOS commad) in other folder all the files .txt; the other folder will contain all the files .txt and will not contain the folder "newfolder":

other folder will has:
a.txt, b.txt, c.txt and d.txt

Thank you Very Much, and sorry my enghish.