In some U.S. states it is illegal to possess and/or carry such a knife in public. In certain jurisdictions, butterfly knives are categorized as a "gravity knife", "switchblade", or "dagger" although they are also occasionally outlawed by name ("butterfly knife").
* The knife is illegal to carry in California if blade length exceeds two inches as with other automatic knives, they are legal to own if kept in your home.
* In New York, the butterfly knife has been determined not to be a gravity knife.
* In Pennsylvania, the butterfly knife is legal for conceal and open carrying. See Commonwealth v. Miles.
* In Utah, Balisong knives are legal as long as they are not concealed.
* In Virginia, the butterfly knife is legal for conceal and open carrying according to state law, although localities can have additional knife laws and restrictions.
regarding Texas -
Section 46.02 of the Texas Penal Code
(a) A person commits an offense if he intentionally, knowingly, or recklessly carries on or about his person a handgun, illegal knife, or club.
(b) Except as provided by Subsection (c), an offense under this section is a Class A misdemeanor.
(c) An offense under this section is a felony of the third degree if the offense is committed on any premises licensed or issued a permit by this state for the sale of alcoholic beverages.
Section 46.01 of the Texas Penal Code:
"Illegal knife" means a:
(A) knife with a blade over five and one-half
(B) hand instrument designed to cut or stab
another by being thrown;
(C) dagger, including but not limited to a dirk,
stiletto, and poniard;
(D) bowie knife;
(E) sword; or
My read on that is that it would not apply to Butterfly Knives unless the blade length exceeded five and a half inches.