This is the 12969th most frequent Turkish word.
kalktığı
"That/which/where (he/she/it) got up" or "departed from."
Here, 'kalktığı' is derived from 'kalkmak' (to get up) and is used in a clause to explain the reason for feeling energetic ('kalktığı için' - because he got up).
Sabah erkenden kalktığı için çok enerjik hissediyordu.
Since he got up early in the morning, he was feeling very energetic.
In this context, 'kalktığı' refers to the action of the plane taking off ('kalkmak' - to take off) and specifies the time it occurred.
Uçağın kalktığı saat kesinlikle belirtilmeliydi.
The departure time of the plane should have definitely been mentioned.
Here, 'kalktığı' indicates the point in time when the person moved away from the table ('kalkmak' - to stand up from a position).