I tried to book a flight through the company's website. It would not allow me to enter the United States as the issuance of the passport and also would not take an American phone number (as part of the reservation process).

Subsequently, I called the customer service phone number to book the flight. The company agent dropped the call 3 times after giving him all the details and documentation. He never completed the transaction and would not call me back despite having my phone number. I tried to make the reservation for 3+ hours. I gave up because I lost confidence in the airlines.

I booked our flights on LATAM instead.

Worst airline experience of my life. Horrible customer service and I watched the employees make multiple customers cry. Extremely strict about luggage and carry one size, and will not let you board the flight if your luggage is even one centimeter too large. We had to buy a ticket for my husband on another airline due to their unreasonable policies. And then there was plenty of space on the flight. I've flown with dozens of economy airlines all over the world and this was by far the worst.

I had originally purchased a refundable fare (thankfully), but SKY airlines preponed the flight up by a few hours, so I had to cancel the refundable ticket.
However, they will not refund the money. Every time I contact them through their website (the only possible way to "contact" them), I receive an automated message saying that the refund will be issued in 10 business days. And the 10 business days keeps resetting.
Thankfully, I booked this with a credit card that comes with purchase protection. I am currently disputing the charge. I'd choose LATAM over Sky any day.

Travelled on an internal flight between the airports which had been booked via a travel agency. We were charged for additional hold baggage when we had already had this included in our original booking. Contacted the airline and after 2 months were told it was because our baggage was overweight/sized even though it wasn’t. We were told at the check in desk that we didn’t have luggage booked and therefore we needed to pay for it. Complained again, another month wait to be told sort it out with the travel agent even though we paid the airline. Would avoid at all costs, they make up the rules as they go along

Péssima companhia. O vôo e os aviões estão em ordem, mas tivemos gastos extras por desonestidade da empresa: compramos bagagens antecipadas e ao chegarmos para despache tivemos que pagar novamente. Na volta, um funcionário buscou bagagens de mãos extras em todos os passageiros que aguardavam para que pudessem cobrar por qualquer bolsa considerada adicional. O baixo preço das bagagens não compensa no fim das contas. Como diz no ditado brasileiro "é o barato que sai caro".

English:
Terrible airline. The flight and planes are fine, but we had extra expenses due to the company's dishonesty: we purchased baggage in advance, and upon check-in, we were charged again. On the return flight, an employee went around collecting extra carry-on bags from all passengers waiting to charge for any bag deemed additional. The low baggage prices are not worth it in the end. As the Brazilian saying goes, "cheap ends up being expensive."

Espanhol:
Pésima compañía. El vuelo y los aviones están bien, pero tuvimos gastos extras por la deshonestidad de la empresa: compramos equipaje por adelantado y, al llegar para despachar, tuvimos que pagar nuevamente. En el regreso, un empleado revisó el equipaje de mano extra de todos los pasajeros que esperaban, para cobrar por cualquier bolsa considerada adicional. Al final, los precios bajos del equipaje no valen la pena. Como dice el dicho brasileño, "lo barato sale caro".