Correct spelling, explanation: the correct form is exiting. It is the present participle of the verb exit, following the standard rule of adding -ing without doubling the final consonant. Exitting is incorrect because the final consonant -t is not doubled. In English, consonant doubling typically happens when a word has a stressed single-syllable ending (e.g., sit → sitting), but exit has the stress on the first syllable (EX-it), so the -t remains single.

Definition of exiting:
Verb (present participle of exit), to leave a place such as a building, room, or large vehicle
The passengers were calmly exiting the train when the announcement was made.
She hesitated for a moment before exiting the crowded room.

Collocations with exiting:
Some of the most commonly used collocations include:
1. Exiting a building: leaving a structure.
The employees were exiting the building when the fire alarm went off.
2. Exiting a vehicle: getting out of a car, bus, plane, etc.
Passengers must remain seated before exiting the aircraft.
3. Exiting a highway: leaving a road via an exit ramp.
He missed his turn and had to take the next opportunity for exiting the highway.
4. Exiting a relationship: ending a romantic or professional connection.
She had a hard time exiting the toxic relationship.

Incorrect spelling, explanation: exitting is a mistake because it incorrectly doubles the final consonant -t in exit when forming the present participle exiting. In English, a final consonant is usually doubled when a word has one syllable (like sit → sitting) or when the last syllable is stressed in a multi-syllable word (like admit → admitting). The word exit has two syllables (EX-it), with the stress on the first syllable, not the last. Because of this, the -t does not get doubled when adding -ing, so the correct form is exiting.