Airlines canceled flights and the US State Department urged Americans to shelter in place on Sunday after violent clashes erupted in western Mexico following a military operation that killed a powerful drug cartel leader.Southwest and Alaska Airlines said they canceled flights to and from Puerto Vallarta, while Delta Air Lines issued travel waivers for passengers flying to or from Puerto Vallarta and Guadalajara. Air Canada also temporarily suspended operations at Puerto Vallarta airport, citing what it described as an “ongoing security situation.”The US State Department issued a security alert advising American citizens in several Mexican states – including Jalisco, Tamaulipas, Michoacan, Guerrero, and Nuevo Leon – to remain indoors until further notice.For all the latest headlines follow our Google News channel online or via the app.The unrest followed an operation by Mexican security forces that killed Nemesio Ruben Oseguera Cervantes, known as “El Mencho,” leader of the Jalisco New