Frontier Airlines will provide free flight vouchers to whoever adopts one of three kittens, who were named after airlines, from a Las Vegas-based animal shelter, the carrier says. The cats — named Frontier, Spirit and Delta — are recent arrivals at the Animal Foundation of Las Vegas, Nevada’s largest animal shelter. The vouchers have been delivered to the shelter, but won’t be distributed until the kittens are ready for adoption in about a month, an airline rep said. “The kittens are a bit young to be adopted out yet, according to what the organization has indicated, but should be ready...