Is RTS CTS Necessary to connect. We have RX TX to do the same work

Hello, Iam using my XBee to PIxhawack and to Mission Planner.
i electrically connected PIXWACK’s gnd tx rx cts rts to my Xbee gnd rx tx cts rts
is it necessary to connects rts to rts and cts to cts even though i have tx rx. what could be the result if i wont connect.

Depending on the settings, the flow control pins might not be needed.
Are they wired correctly?

Thank you for answering
But when i connected tx rx electrically to pixhawk mission planner gave many packet losses. so i connected RTS-RTS & CTS-CTS electrically i got no packet losses. But my question is cant i reduce my packet losses ny just connecting RX-Tx & Tx-Rx
Thank you