Because wired connections make changing the seating configuration difficult, a wireless client device enables stable wireless transmission. The wireless client device wirelessly transmits to and receives data signals from an access point inside an aircraft. The wireless client device has a seat unit with a seat portion on which aircraft passengers sit, an antenna for sending and receiving the data signals, a signal processing arrangement operable to handle data signal receiving and transmitting processes, and a signal output arrangement operable to output processed reception signals. The antenna arrangement, signal processing arrangement, and signal output arrangement are disposed to the seat unit.