I travel internationally frequently - never had any problem. I have a middle name on the passport, but the ticket shows only the middle initial.

Please keep in mind that there is a limited number of spaces allocated to the name on the ticket.

So if the sum of your last name, first name, and middle name exceeds 20 characters, Delta will truncate in this order:

1) The middle name will only show as an initial, and
2) Your first name will be truncated and only show its first few letters.