Learn Dutch: Ze zeggen het reisplan is leuk, want de reistijd is kort. - They say the itinerary is fun, because the travel time is short.

This sentence drops the word dat (that), which is a common habit in spoken Dutch after verbs of speech or thought like zeggen (to say). When you omit dat, the clause is no longer treated as a subordinate clause, so it reverts to the standard V2 main clause word order instead of pushing the verb to the end.

Would it be wrong to include the word dat in this sentence?

Not at all! Including dat makes the sentence more formal and standard for written Dutch. However, if you add it back in, you must apply subordinate clause word order and move the verb to the end: Ze zeggen dat het reisplan leuk is.

Why does the verb stay in the second position after want?

The word want (because) is a coordinating conjunction, which means it links two independent main clauses. Main clauses always use the standard V2 word order. If you used the synonym omdat instead, it would act as a subordinating conjunction and push the verb to the end: omdat de reistijd kort is.

Both reisplan and reistijd start with reis, but one uses het and the other uses de. Why?