Multiple airlines have begun offering direct flights between the mainland US and Cuba and each airline individually manages the processes and requirements. It is up to you to contact your airline to ask about any of the procedures. Usually, flying through the US requires any citizen of any nationality to declare the travel complies with the licensed travel to Cuba. 

UPDATE JUNE 2019: We recommend our travellers do not fly through the US to Cuba. 

Based on newly implemented restrictions to Cuba travel for US citizens, we do not accept US passport holders on our trips to Cuba. 

International credit cards and debit cards, including US credit cards and debit cards, are officially accepted in Cuba. However, we still do not recommend that anyone, of any nationality, rely on debit or credit as a payment method while in Cuba. The fact that Cuba "officially" accepts all cards does not mean that everywhere has the infrastructure to accept them. In fact, very few establishments in Cuba are actually equipped to accept any cards, especially in the smaller towns. Cash is king in Cuba, especially outside of Havana. It is best to arrive into Cuba with sufficient cash as well because many of the ATMs in Cuba do not work or are out of cash and unable to dispense you any money. Thus, it is best to always have sufficient backup cash on hand from the moment you arrive. Upon arrival, you can convert money into the local currency for spending. You will be unable to purchase Cuba's local currency outside of Cuba at your bank in your home country. Cuba's currency must be purchased/converted upon arrival into Cuba. 

"Casa particular" is Spanish for "private house." These are basic Cuban style accommodations, giving you a closer connection to life in Cuba. During these stays, especially at meal times, guests have many opportunities to communicate and have meaningful interactions with the host. You might call it the Cuban equivalent to what you know in other countries as a homestay or Bed 'n Breakfast. Even if you do not speak Spanish, carrying a Spanish phrasebook will go a long way to to helping you connect with your host. Staying at private houses connects you directly with Cuba's people, culture and way of life. The interactions at the casa stays are often a true highlight of the trip for BikeHike's Cuba travellers.