These are all examples of giving advice, which depends greatly on placing emphasis on certain words. In the first two sentences, the emphasis is on two things:

1- What the third-person-noun is doing

2- The adverb

**We recommend** you book your flight **early**
**He recommends** reading the book **before** watching the movie.

Notice that "to" is not required in the first sentence. Should "to" be required, it would be best to swap out "recommend" for "advise."

**We advise** you to book your flight **early**

These are all examples of giving advice, which depends greatly on placing emphasis on certain words. In the first two sentences, the emphasis is on two things:

1- What the third-person-noun is doing

2- The adverb

We recommend you book your flight early
He recommends reading the book before watching the movie.

Notice that "to" is not required in the first sentence. Should "to" be required, it would be best to swap out "recommend" for "advise."

We advise you to book your flight early