Is Palestine still a part of Israel?
Palestine is under Israel's control after they won it in the 1967 six day war.
The West Bank was controlled by Jordan, the Gaza Strip and Peninsula from Egypt and the Golan Heeghts from Syria
There is no such place as Palestine, and there are no such people as "Palestinians." It is an historical fiction invented in the mid-1960s for anti-Semitic public relations purposes.
Gaza and parts of Judea/Samaria (erroneously referred to as the "west bank") are under Arab control. But all still belong to Israel.
BTW, according to the Balfour Declaration of 1922, all of Jordan also belongs to Israel too, comprising the Biblical and historical land of Israel.