I miss traveling, the fun of going new places, seeing new sights, and eating at new restaurants. I get to travel frequently for work, which has it upsides and downsides at times. I am gone a lot, but many times I do get to visit places i like to see and places I have never been before. As well as the perks you can get when your a frequent traveler with some airlines and hotels.
I not sure I want to get on a plane right now due to the current pandemic situations, but I sure do miss the excitement of visiting places. I miss staying at new hotels with different amenities to enjoy, as well as scouting out new places to eat.
I prefer to fly Delta as I have Diamond status with them at this current time and they have always treated me well so far. I do fly AA and United when I have to, as Delta does not always go where I need to travel. I used to be a United person but really began to have issues with them several years back and switched up to Delta, and have not had any major issues since in my travels (besides weather related issues). As for AA, they are not that great out of Knoxville Airport (TYS), not sure if it was from the merger with US Airways a few years back or what, but they seem to have the most delays and cancellations from TYS (In my opinion). I always see them on the status boards with Delayed or Canceled, I am sure some of it is due to TYS being a hub for most airlines, but AA seems to have issues very frequently there.
I also prefer to stay at Hilton Hotels, Marriott Hotels and when possible Hyatt Hotels. I have been loyal to Hilton for several years now, but more and more I am staying with Marriott. I made Lifetime Silver with Marriott and am super close to Lifetime Gold (60 Nights needed). 
With Hilton I have several more years (5 years to go) to make Lifetime Diamond as they did not count a couple of years I was Diamond with them before they began the program and getting to 1000 nights will take a few more years. I am over halfway there, but when they do not have decent places to stay or they are too expensive to stay at in some areas, I will pick another brand. With Marriott they have a tier system so you can get to a specific status level sooner. I made their Silver Status late last year, and had been slowly working my way up to Gold Status early this year. However, with not traveling as much lately it has slowed my progress a lot.
For car rental companies I am switching it up to who ever gives me the best options. Have been using Hertz lately as I could do grab and go option similar to National.
However, with National it seems unless you have their higher tier status you do not get the nicer cars to drive as often lately. That was not the case when I first started using National, but had begin to change over time. It is not a big issue most of the time, but I do prefer to get something that is comfortable to drive and not a piece of crap. I do like how Hertz has gone to using Clear (when it really works), I noticed it goes a little quicker at the gates to check out when it works.
So all in all with the pandemic I might be changing up some of my travel preferences. I have got the Amex Platinum and Amex Gold cards, and will be looking to downgrade the Amex Delta Reserve card to the free Amex Delta Blue card. As I might be changing up my flying strategy with one airline due to lack of travel and ability to keep status. I am also looking to get the Chase Hyatt card to help with keep my Discoverist Status with them, as I might not get to stay at they properties much next year. I already have the Amex Hilton Aspire card and Chase Marriott Bonvoy card to help with earning points during my stays at their properties.
Planning to leverage the Amex Platinum card for booking flights and my Amex Gold card for dinning out and groceries, and my specific hotel branded cards for hotel stays. The Amex Platinum gets me Delta Lounge access when flying with Delta, as well Centurion and Priority Pass lounges where available when flying other carriers. With the Amex points I can transfer to partners to book flights with points and am not tied to one specific airline. I will miss the status from Delta, but not sure I will be getting much past Gold status after next year unless things pick up and we start traveling a lot more. We will see how that goes for 2021, and may switch back to some previous strategies in 2022 if the travel gets back to normal.