Construed with for.
- Travel for business purposes, often paid for at least partially by the employer.
1898, Winston Churchill, chapter 2, in The Celebrity:
- I had occasion […] to make a somewhat long business trip to Chicago, and on my return […] I found Farrar awaiting me in the railway station. He smiled his wonted fraction by way of greeting, […] and finally leading me to his buggy, turned and drove out of town. I was completely mystified at such an unusual proceeding.