The ornamental design for an aircraftseat, as shown and described.
FIG. 1 is a front and side perspective view of an aircraft seat;
FIG. 2 is a front and opposite side perspective view thereof;
FIG. 3 is a rear and side perspective view thereof;
FIG. 4 is a side elevational view thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is an opposite side elevational view thereof;
FIG. 7 is a front elevational view thereof; and,
FIG. 8 is a rear elevational view thereof.
The broken lines in FIGS. 1-8 represent portions of the aircraft seat that form no part of the claimed design. The bottom view forms no part of the claimed design.