Texas penal code title 5, chapter 20, section 20.03:
KIDNAPPING. (a) A person commits an offense if he intentionally or knowingly abducts another person.
Abduct is defined in section 20.01(2):
(2) "Abduct" means to restrain a person with intent to prevent his liberation by: (A) secreting or holding him in a place where he is not likely to be found --snip--
Per reports, the alleged undocumented immigrants are induced with imaginary benefits (such as expedited asylum claims) and are sent to destinations unknown by them. If you don't know where you're going, you're not likely to be found.
At the very least it'd be unlawful restraint.
Sec. 20.02. UNLAWFUL RESTRAINT. (a) A person commits an offense if he intentionally or knowingly restrains another person.
Restrain is defined in section 20.01(1):
(1) "Restrain" means to restrict a person's movements without consent, so as to interfere substantially with the person's liberty, by moving the person from one place to another or by confining the person. Restraint is "without consent" if it is accomplished by:
(A) force, intimidation, or deception --snip--
The alleged undocumented immigrants are being induced onto these bus and/or planes by false promises (e.g. expedited asylum claims elsewhere). Which means they're being trafficked somewhere else via deception.