Here's how to mount a remote filesystem and use it as if it were local, using sshfs in bash to an EC2 server using a pem file (note: replaceable options in CAPS_AND_UNDERSCORES):
mkdir <MY_PATH>
sshfs -o IdentityFile=<PATH_TO_PEM_FILE> EC2_USERNAME@<EC2_IP_OR_DOMAIN_NAME>:/<OPTIONAL_FOLDER_PATH> <MY_PATH>
This will mount the remote filesystem to <MY_PATH> and allow you to do your file transfers. Of course permissions still matter, so keep those in mind if you start having write-protect errors.
To unmount from the remote filesystem:
umount <MY_PATH>
